Resin composition, cured product, prepreg, metal foil-clad laminate, resin composite sheet, printed wiring board, and semiconductor device

Abstract

Provided are a resin composition, a cured product, a prepreg, a metal foil-clad laminate, a resin composite sheet, a printed wiring board, and a semiconductor device. This resin composition comprises an elastomer (A), a thermosetting compound (B), a radical polymerization initiator (C), and a filling material (D), wherein: the elastomer (A) includes a polymer block (a1) containing a radically reactive group-containing styrene compound unit and a conjugated diene compound unit; the thermosetting compound (B) contains a resin (E) having at least two vinylbenzyl groups at the terminal thereof; the content of the filling material (D) is 1-300 parts by mass with respect to 100 parts by mass of the solid content of the resin; and the mass ratio ((A) / (E)) of the elastomer (A) to the resin (E) having at least two vinylbenzyl groups at the terminal thereof is 0.01-1.1.

Description

Resin composition, cured product, prepreg, metal foil-clad laminate, resin composite sheet, printed wiring board, and semiconductor device

[0001] The present invention relates to a resin composition, a cured product, a prepreg, a metal foil-clad laminate, a resin composite sheet, a printed wiring board, and a semiconductor device.

[0002] In recent years, the integration and miniaturization of semiconductor elements used in mobile devices, electronic devices, communication devices, and other devices has accelerated. This has led to a demand for technologies that enable high-density packaging of semiconductor elements, and improvements are also being sought in printed wiring boards, such as substrates for mounting semiconductor elements, which play an important role in this process. Meanwhile, the applications of electronic devices and other devices have continued to diversify and expand. Accordingly, the properties required for printed wiring boards, such as substrates for mounting semiconductor elements, and for the metal foil-clad laminates and prepregs used therein, have become more diverse and demanding. Taking these required properties into account, various materials and processing methods have been proposed to obtain improved printed wiring boards. One example is the development of improved resin materials for prepregs and resin composite sheets.

[0003] For example, Patent Document 1 discloses a curable resin composition containing (A) a modified polyphenylene ether having a silyl group-containing group, (B) a styrene-based elastomer, (C) a cross-linking aid which is an aromatic vinyl compound represented by a predetermined formula and having three or less vinyl groups in the molecule, (D) a liquid elastomer, and (E) a vinyl group-containing silane-based compound represented by a predetermined formula.

[0004] JP 2023-141184 A

[0005] As described in Patent Document 1, blending an elastomer into a curable resin composition tends to improve low dielectric properties, but also tends to increase the coefficient of thermal expansion (CTE). The present invention aims to solve this problem and to provide a resin composition that, when cured, maintains low dielectric properties while exhibiting low thermal expansion and excellent heat resistance, as well as a cured product, a prepreg, a metal foil-clad laminate, a resin composite sheet, a printed wiring board, and a semiconductor device.

[0006] In light of the above-mentioned problems, the present inventors conducted research and found that the above-mentioned problems can be solved by using an elastomer containing a polymer block including styrene compound units having radical-reactive groups, and by using a filler. Specifically, the above-mentioned problems were solved by the following means. [1] A resin composition comprising: an elastomer (A), a thermosetting compound (B), a radical polymerization initiator (C), and a filler (D), wherein the elastomer (A) comprises a polymer block (a1) including styrene compound units and conjugated diene compound units having radical-reactive groups, and the thermosetting compound (B) comprises a resin (E) having two or more vinylbenzyl groups at its terminals, the content of the filler (D) being 1 to 300 parts by mass per 100 parts by mass of resin solids, and the mass ratio ((A) / (E)) of the elastomer (A) to the resin (E) having two or more vinylbenzyl groups at its terminals is 0.01 to 1.1. [2] The resin composition according to [1], wherein the radical-reactive group comprises a methyl group. [3] The resin composition according to [1] or [2], wherein the styrene compound units having a radical reactive group comprise p-methylstyrene units. [4] The resin composition according to any one of [1] to [3], wherein the conjugated diene compound units comprise butadiene units and / or isoprene units. [5] The resin composition according to any one of [1] to [4], wherein the conjugated diene compound units comprise hydrogenated or partially hydrogenated butadiene units and / or hydrogenated or partially hydrogenated isoprene units. [6] The resin composition according to any one of [1] to [5], wherein the conjugated diene compound units comprise butylene units and / or ethylene units. [7] The resin composition according to any one of [1] to [6], wherein the elastomer (A) further comprises a polymer block (a2) comprising a styrene compound unit optionally having a radical reactive group and / or a polymer block (a3) ​​comprising a conjugated diene compound unit. [8] The resin composition according to [7], wherein the styrene compound unit optionally having a radical reactive group in the polymer block (a2) contains a p-methylstyrene unit, and the conjugated diene compound unit in the polymer block (a3) ​​contains a hydrogenated or partially hydrogenated butadiene unit and / or a hydrogenated or partially hydrogenated isoprene unit.[9] The resin composition according to any one of [1] to [8], wherein the content of styrene compound units having a radical reactive group in 100 mass% of the polymer block (a1) is 10 to 80 mass%.

[10] The resin composition according to any one of [1] to [9], wherein the content of styrene compound units having a radical reactive group in 100 mass% of the elastomer (A) is 10 to 70 mass%.

[11] The resin composition according to any one of [1] to

[10] , wherein the maximum temperature of the Tan δ peak of the elastomer (A) measured by dynamic mechanical analysis (DMA) at a frequency of 10 rad / s is -30 to 80°C.

[12] The resin composition according to any one of [1] to

[11] , wherein the content of the elastomer (A) is 0.5 to 30 parts by mass per 100 parts by mass of the resin solid content.

[13] The styrene compound unit having a radical reactive group comprises a p-methylstyrene unit, the conjugated diene compound unit comprises a hydrogenated or partially hydrogenated butadiene unit and / or a hydrogenated or partially hydrogenated isoprene unit, the elastomer (A) further comprises a polymer block (a2) comprising a styrene compound unit optionally having a radical reactive group and / or a polymer block (a3) ​​comprising a conjugated diene compound unit, the styrene compound unit optionally having a radical reactive group of the polymer block (a2) comprises a p-methylstyrene unit, and the conjugated diene compound unit of the polymer block (a3) ​​comprises a hydrogenated or partially hydrogenated butadiene unit and / or a hydrogenated or partially hydrogenated isoprene unit, the content of the styrene compound unit having a radical reactive group in 100% by mass of the polymer block (a1) is 10 to 80% by mass, and the content of the styrene compound unit having a radical reactive group in 100% by mass of the elastomer (A) is 10 to 70% by mass, The resin composition according to any one of [1] to

[12] , wherein the elastomer (A) has a maximum temperature of Tan δ peak in dynamic mechanical analysis (DMA) measured at a frequency of 10 rad / s of −30 to 80° C., and the content of the elastomer (A) is 0.5 to 30 parts by mass per 100 parts by mass of resin solid content.

[14] The resin composition according to any one of [1] to

[13] , wherein the resin (E) having two or more vinylbenzyl groups at its terminals comprises a polyphenylene ether compound having two or more vinylbenzyl groups at its terminals, and / or a polymer having a structural unit represented by formula (V). (In formula (V), Ar represents an aromatic hydrocarbon linking group. * represents a bonding position.)

[15] The resin composition according to any one of [1] to

[14] , wherein the resin (E) having two or more vinylbenzyl groups at its terminals contains a polyphenylene ether compound represented by formula (OP). (In formula (OP), X represents an aromatic group, and —(Y—O) ｎ１ - represents a polyphenylene ether structure, n1 represents an integer of 1 to 100, and n2 represents an integer of 1 to 4. Rx is a group represented by formula (Rx-1). (In formula (Rx-1), R １ , R ２ , and R ３each independently represent a hydrogen atom, an alkyl group, an alkenyl group, or an alkynyl group. * represents a bonding site with an oxygen atom. Each Mc independently represents a hydrocarbon group having 1 to 12 carbon atoms. z represents an integer of 0 to 4. r represents an integer of 0 to 6.)

[16] The resin composition according to any one of [1] to

[15] , wherein the content of the resin (E) having two or more vinylbenzyl groups at its terminals is 1 part by mass or more and 60 parts by mass or less per 100 parts by mass of the resin solid content in the resin composition.

[17] The resin composition according to any one of [1] to

[16] , wherein the thermosetting compound (B) further contains a maleimide compound.

[18] The resin composition according to any one of [1] to

[17] , wherein the radical polymerization initiator (C) contains an organic peroxide.

[19] The resin composition according to any one of [1] to

[18] , wherein the filler (D) contains hollow silica.

[20] The resin composition according to any one of [1] to

[19] , further comprising a flame retardant.

[21] The resin composition according to any one of [1] to

[20] , wherein the thermosetting compound (B) comprises an aromatic-containing resin having a terminal carbon-carbon double bond, the thermosetting compound (B) further comprises a maleimide compound, the radical polymerization initiator (C) comprises an organic peroxide, and the filler (D) comprises hollow silica, and further comprises a flame retardant.

[22] A cured product of the resin composition according to any one of [1] to

[21] .

[23] A prepreg formed from a substrate and the resin composition according to any one of [1] to

[21] .

[24] A metal foil-clad laminate comprising at least one layer formed from the prepreg according to

[23] and metal foil disposed on one or both sides of the layer formed from the prepreg.

[25] A resin composite sheet comprising a support and a layer formed from the resin composition according to any one of [1] to

[21] , disposed on the surface of the support.

[26] A printed wiring board comprising an insulating layer and a conductor layer disposed on a surface of the insulating layer, wherein the insulating layer comprises a layer formed from the resin composition according to any one of [1] to

[21] .

[27] A semiconductor device comprising the printed wiring board according to

[26] .

[0007] The present invention makes it possible to provide a resin composition that, when cured, maintains low dielectric properties while exhibiting low thermal expansion and excellent heat resistance, as well as a cured product, a prepreg, a metal foil-clad laminate, a resin composite sheet, a printed wiring board, and a semiconductor device.

[0008] Hereinafter, a detailed description of an embodiment of the present invention (hereinafter simply referred to as "the present embodiment") will be given. Note that the following present embodiment is an example for explaining the present invention, and the present invention is not limited to this embodiment. In this specification, the term "to" is used to mean that the numerical values ​​before and after it are included as the upper and lower limits. Furthermore, any combination of the upper and lower limit values ​​of numerical values ​​in this specification is cited as an example of this embodiment. In this specification, various physical property values ​​and characteristic values ​​are those at 23°C unless otherwise specified. In this specification, when a group (atomic group) is described without specifying whether it is substituted or unsubstituted, it encompasses both a group (atomic group) that has no substituent and a group (atomic group) that has a substituent. For example, the term "alkyl group" encompasses not only an alkyl group that has no substituent (unsubstituted alkyl group) but also an alkyl group that has a substituent (substituted alkyl group). In this specification, when a term without specifying whether it is substituted or unsubstituted, it is preferred that it be unsubstituted. Examples of the substituent in this specification are preferably a halogen atom, a cyano group, a nitro group, a hydroxy group, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, a heterocyclic group, a heterocyclicoxy group, an alkenyl group, an alkylsulfanyl group, an arylsulfanyl group, an acyl group, or an amino group, more preferably a halogen atom, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an alkenyl group, or an acyl group, even more preferably an alkyl group, an aryl group, an aryloxy group, or an alkenyl group, and still more preferably an alkyl group. The formula weight of these substituents is preferably 15 or more, and preferably 200 or less. The formula weight is, for example, the formula weight of a methyl group (-CH ３ ) is 15. These substituents may further have a substituent, but it is preferable that they have no substituent.

[0009] In this specification, "(meth)allyl" refers to either or both of allyl and methallyl, "(meth)acrylate" refers to either or both of acrylate and methacrylate, "(meth)acrylic" refers to either or both of acrylic and methacrylic, and "(meth)acryloyl" refers to either or both of acryloyl and methacryloyl.

[0010] In this specification, the resin solid content refers to components excluding the filler (D) and the solvent, and is intended to include the elastomer (A), the thermosetting compound (B), the radical polymerization initiator (C), as well as other components that are blended as necessary, and resin additive components (additives such as flame retardants, etc.). In this specification, the terms relative permittivity and dielectric constant are used interchangeably.

[0011] If the measurement methods, etc. described in the standards shown in this specification vary from year to year, they will be based on the standards in effect as of January 1, 2024, unless otherwise specified. If the measurement methods, etc. described in the standards shown in this specification are abolished as of January 1, 2024, they will be based on the standards in effect at the time of abolition.

[0012] The resin composition of this embodiment comprises an elastomer (A), a thermosetting compound (B), a radical polymerization initiator (C), and a filler (D). The elastomer (A) comprises a polymer block (a1) containing a styrene compound unit having a radical-reactive group and a conjugated diene compound unit. The thermosetting compound (B) comprises a resin (E) having two or more vinylbenzyl groups at its terminals. The content of the filler (D) is 1 to 300 parts by mass per 100 parts by mass of the resin solids. The mass ratio ((A) / (E)) of the elastomer (A) to the resin (E) having two or more vinylbenzyl groups at its terminals is 0.01 to 1.1. This configuration allows for the provision of a resin composition that, when cured, exhibits low thermal expansion and excellent heat resistance (solder heat resistance) while maintaining low dielectric properties (Dk and / or Df). Furthermore, the resulting cured product tends to be less prone to void formation.

[0013] Generally, resin compositions containing a thermosetting compound and an elastomer tend to exhibit improved low dielectric properties when cured. However, the resulting cured product tends to have a high coefficient of thermal expansion (CTE). Under these circumstances, the present inventors decided to employ an elastomer (A) containing a polymer block (a1) including a styrene compound unit having a radical-reactive group and a conjugated diene compound unit. Because the styrene compound unit in the elastomer (A) contains a radical-reactive group, the radical polymerization initiator (C) abstracts hydrogen from the radical-reactive group, generating radicals, which allows the elastomer (A) to undergo a crosslinking reaction with the thermosetting compound (B). It is believed that the crosslinking reaction between the elastomer (A) and the thermosetting compound (B) effectively suppresses thermal expansion in addition to providing low dielectric properties (Dk and / or Df). More specifically, when heat is applied to the resin composition, the components derived from the thermosetting compound (B) shrink and expand, causing deformation. However, since the elastomer (A) itself has an inherently flexible skeleton, it is believed to have the effect of alleviating the stress imparted by heat, thereby suppressing thermal expansion. In particular, by adjusting the mass ratio of elastomer (A) to resin (E) having two or more vinylbenzyl groups at its terminals to 0.01 to 1.1, various physical properties, particularly heat resistance (glass transition temperature), can be improved. That is, it is believed that a high content of elastomer (A) results in poor compatibility with resin (E) having two or more vinylbenzyl groups at its terminals, resulting in poor physical properties of the cured product. In addition, the resin composition of this embodiment more effectively suppresses thermal expansion by incorporating filler (D). This is believed to be because filler (D) acts to relieve stress during curing of the resin composition, thereby suppressing deformation. On the other hand, if the content of filler (D) is too high, the resulting cured product tends to have poor solder heat resistance and voids tend to be easily formed during molding into a cured product. In the resin composition of this embodiment, by setting the content of filler (D) to 300 parts by mass or less per 100 parts by mass of the resin solid content, the solder heat resistance tends to be excellent and the formation of voids in the cured product tends to be suppressed.The details of this embodiment will be described below.

[0014] <Elastomer (A)> The resin composition of this embodiment includes an elastomer (A) containing a polymer block (a1) including a styrene compound unit having a radical-reactive group and a conjugated diene compound unit. The elastomer (A) may further include a polymer block (a2) including a styrene compound unit optionally having a radical-reactive group and / or a polymer block (a3) ​​including a conjugated diene compound unit. Furthermore, the elastomer (A) may contain a polymer block other than the polymer blocks (a1) to (a3) ​​without departing from the spirit of this embodiment. By using such an elastomer (A) including a polymer block (a1) including a styrene compound unit having a radical-reactive group and a conjugated diene compound unit, a resin composition can be obtained that, when cured, has a low thermal expansion coefficient while maintaining low dielectric properties (Dk and / or Df). More specifically, the elastomer (A) contains a styrene compound unit having a radical reactive group as the polymer block (a1), or as both the polymer block (a1) and the polymer block (a2), so that when the elastomer (A) is cured, it forms a crosslinked structure with the thermosetting compound (B), thereby effectively suppressing thermal expansion. Furthermore, the elastomer (A) contains a conjugated diene compound unit as the polymer block (a1), or as both the polymer block (a1) and the polymer block (a3), so that when the elastomer (A) is cured, it exhibits excellent low dielectric properties (Dk and / or Df).

[0015] The elastomer (A) contains a polymer block (a1) (sometimes simply referred to as "polymer block (a1)" in this specification) containing a styrene compound unit having a radical reactive group and a conjugated diene compound unit. The polymer block (a1) is preferably a copolymer block containing a styrene compound unit having a radical reactive group and a conjugated diene compound unit.

[0016] A radically reactive group refers to a chemical group that is capable of forming, or can be induced to form, a free radical species. The free radical species can be formed by any known means, including thermal means, photochemical means, or chemical reagents. For example, CHR ２ -CHR in the structure of the benzene ring ２ The portion may be a radical reactive group. Here, each R is independently a hydrogen atom or a monovalent alkyl group having 1 to 3 carbon atoms, preferably a hydrogen atom or a methyl group, and more preferably all R are hydrogen atoms. Another example of a radical reactive group is a cyclobutane ring, which can be activated, for example, by light, to form a free radical species. Another example of a radical reactive group is an allyl group, which can form an allyl free radical. In this embodiment, the radical reactive group preferably includes a methyl group.

[0017] As the styrene compound having a radical reactive group, a compound represented by any one of formulas (I) to (IV) is preferred, and a compound represented by formula (I) is more preferred. (In formula (I), each R independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. In formulas (I) to (IV), R １ represents a hydrogen atom or a methyl group.

[0018] In formula (I), each R is preferably independently a hydrogen atom, a methyl group, or an ethyl group, and more preferably all R are hydrogen atoms. ２ The substituent represented by the formula (I) to (IV) may be bonded at any of the ortho, meta, and para positions, but is preferably bonded at the ortho or para position, and more preferably at the para position. １ is preferably a hydrogen atom.

[0019] Specifically, the styrene compound unit having a radical reactive group is preferably at least one selected from the group consisting of an o-methylstyrene unit, a p-methylstyrene unit, an o-ethylstyrene unit, a p-ethylstyrene unit, an o-isopropylstyrene unit, a p-isopropylstyrene unit, an o-methyl-α-methylstyrene unit, a p-methyl-α-methylstyrene unit, an o-ethyl-α-methylstyrene unit, a p-ethyl-α-methylstyrene unit, an o-isopropyl-α-methylstyrene unit, and a p-isopropyl-α-methylstyrene unit, and more preferably contains a p-methylstyrene unit.

[0020] The content of the styrene compound units having a radical reactive group in the polymer block (a1) is preferably 10% by mass or more, more preferably 20% by mass or more, based on 100% by mass of the polymer block (a1). Depending on the application, it may be 25% by mass or more, 30% by mass or more, and preferably 80% by mass or less, more preferably 70% by mass or less. Depending on the application, it may be 65% by mass or less, 60% by mass or less. By setting the content of the styrene compound units having a radical reactive group in the polymer block (a1) to the above lower limit or more, the number of crosslinking reaction sites with the thermosetting compound (B) increases, and heat resistance and low thermal expansion properties tend to be further improved. Furthermore, by setting the content of the styrene compound units having a radical reactive group in the polymer block (a1) to the above upper limit or less, low dielectric properties tend to be further improved. The polymer block (a1) may contain only one type of styrene compound unit having a radical reactive group, or two or more types. When two or more types are contained, the total amount is preferably within the above range.

[0021] The polymer block (a1) contains a conjugated diene compound unit. The conjugated diene compound unit preferably contains at least one selected from the group consisting of a butadiene unit, an isoprene unit, a 2,3-dimethyl-1,3-butadiene unit, a 1-phenyl-1,3-butadiene unit, a 1,3-pentadiene unit, a 1,3-hexadiene unit, a 3-butyl-1,3-octadiene unit, a farnesene unit, a myrcene unit, a piperylene unit, and a cyclohexadiene unit, more preferably contains a butadiene unit and / or an isoprene unit, and even more preferably contains at least a butadiene unit. In this specification, unless otherwise specified, the conjugated diene compound unit may be hydrogenated, partially hydrogenated, or non-hydrogenated, and is more preferably hydrogenated and / or partially hydrogenated.

[0022] In this embodiment, the conjugated diene compound units more preferably contain hydrogenated or partially hydrogenated butadiene units and / or hydrogenated or partially hydrogenated isoprene units. The conjugated diene units are preferably 1,3-butadiene units, and more preferably hydrogenated or partially hydrogenated 1,3-butadiene units. Typically, hydrogenated butadiene units contain butylene units and / or ethylene units. Furthermore, hydrogenated isoprene units contain ethylene units and propylene units. In this embodiment, the conjugated diene compound units preferably contain butylene units and / or ethylene units. By containing butylene units and / or ethylene units, low dielectric properties and flexibility tend to be further improved.

[0023] The content of the conjugated diene compound unit in the polymer block (a1) is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 30% by mass or more, based on 100% by mass of the polymer block (a1). Depending on the intended use, the content may be 35% by mass or more, 40% by mass or more, and preferably 90% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less. Depending on the intended use, the content may be 75% by mass or less, 70% by mass or less. By setting the content of the conjugated diene compound unit to the above-mentioned lower limit or more, the compatibility with the thermosetting compound (B) (particularly the resin (E) having two or more vinylbenzyl groups at its terminals) in the resin composition tends to be further improved. Furthermore, by setting the content of the conjugated diene compound unit to the above-mentioned upper limit or less, the low dielectric properties tend to be further improved. The polymer block (a1) may contain only one type of conjugated diene compound unit, or may contain two or more types. When two or more types are contained, the total amount is preferably within the above-mentioned range. The total amount of the styrene compound units having a radical reactive group and the conjugated diene units contained in the polymer block (a1) does not exceed 100% by mass.

[0024] The polymer block (a1) may or may not contain a monomer unit (other monomer unit) other than the styrene compound unit having a radical reactive group and the conjugated diene compound unit. Examples of the other monomer unit that may be contained in the polymer block (a1) include at least one selected from the group consisting of a styrene unit, a substituted styrene unit (excluding a styrene compound unit having a radical reactive group), a vinylnaphthalene unit, a substituted vinylnaphthalene unit, a vinylindene unit, a vinylanthracene unit, a 1,1-diphenylethylene unit, a vinylnaphthalene unit, a vinyltoluene unit, and a vinylxylene unit.

[0025] In the polymer block (a1), the total amount of the styrene compound units and conjugated diene compound units having a radical reactive group is preferably 85% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, based on 100% by mass of the polymer block (a1). It may be 99% by mass or more, or even 100% by mass.

[0026] The elastomer (A) used in this embodiment may contain a polymer block other than the polymer block (a1) described above. Specifically, the elastomer (A) preferably further contains a polymer block (a2) (sometimes simply referred to as "polymer block (a2)" herein) containing a styrene compound unit optionally having a radical reactive group, and / or a polymer block (a3) ​​(sometimes simply referred to as "polymer block (a3)" herein) containing a conjugated diene compound unit.

[0027] When the styrene compound unit which may have a radical reactive group in the polymer block (a2) contains a styrene compound unit having a radical reactive group, the styrene compound unit having a radical reactive group has the same meaning as that described for the polymer block (a1) above, and preferred embodiments are also the same. Examples of the styrene compound unit other than the styrene compound unit having a radical reactive group include a styrene unit and a substituted styrene unit (excluding a styrene compound unit having a radical reactive group).

[0028] The content of the styrene compound unit optionally having a radical reactive group in the polymer block (a2) is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, still more preferably 95% by mass or more, even more preferably 99% by mass or more, and may be 100% by mass, based on 100% by mass of the polymer block (a2). The content of the styrene compound unit optionally having a radical reactive group in the polymer block (a2) is preferably 30% by mass or more, more preferably 50% by mass or more, still more preferably 80% by mass or more, even more preferably 90% by mass or more, still more preferably 95% by mass or more, and may be 99% by mass or more, or may be 100% by mass, based on 100% by mass of the polymer block (a2).

[0029] The conjugated diene compound units in the polymer block (a3) ​​have the same meanings and preferred embodiments as those described for the polymer block (a1). The content of the conjugated diene compound units in the polymer block (a3) ​​is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and even more preferably 99% by mass or more, based on 100% by mass of the polymer block (a3), and may be 100% by mass.

[0030] In this embodiment, the polymer block (a2) and the polymer block (a3) ​​may each independently contain, or may not contain, other monomer units other than the styrene compound unit and the conjugated diene compound unit, which may have a radical reactive group. Examples of other monomer units that may be contained in the polymer block (a2) and the polymer block (a3) ​​include, independently, at least one selected from the group consisting of a vinylnaphthalene unit, a substituted vinylnaphthalene unit, a vinylindene unit, a vinylanthracene unit, a 1,1-diphenylethylene unit, a vinylnaphthalene unit, a vinyltoluene unit, and a vinylxylene unit.

[0031] In the elastomer (A) of this embodiment, the above-mentioned polymer blocks are preferably bonded by coupling.

[0032] In this embodiment, the content of the styrene compound units having a radical reactive group in the elastomer (A) (the total amount of the styrene compound units having a radical reactive group contained in the polymer block (a1), polymer block (a2), etc.) is preferably 10% by mass or more, more preferably 15% by mass or more, even more preferably 20% by mass or more, even more preferably 25% by mass or more, even more preferably 30% by mass or more, even more preferably 40% by mass or more, and is preferably 80% by mass or less, more preferably 70% by mass or less, even more preferably 60% by mass or less, even more preferably 55% by mass or less, and even more preferably 50% by mass or less. By setting the content of the styrene compound units having a radical reactive group in the elastomer (A) to the above-mentioned lower limit or more, the number of crosslinking reaction sites with the thermosetting compound (B) increases, and the heat resistance and low thermal expansion properties tend to be further improved. Furthermore, by setting the content of the styrene compound units having a radical reactive group in the elastomer (A) to the above-mentioned upper limit or less, the low dielectric properties tend to be further improved.

[0033] The content of conjugated diene units in the elastomer (A) (total amount of conjugated diene units in the polymer blocks (a1), (a3), etc.) is preferably 20% by mass or more, more preferably 30% by mass or more, even more preferably 35% by mass or more, still more preferably 40% by mass or more, even more preferably 45% by mass or more, and even more preferably 50% by mass or more. It is also preferably 90% by mass or less, more preferably 85% by mass or less, even more preferably 80% by mass or less, even more preferably 75% by mass or less, even more preferably 70% by mass or less, and even more preferably 60% by mass or less. By setting the content of conjugated diene units in the elastomer (A) to the above-mentioned lower limit or more, compatibility with the thermosetting compound (B) (particularly the resin (E) having two or more vinylbenzyl groups at its terminals) in the resin composition tends to be further improved. By setting the content of conjugated diene units in the elastomer (A) to the above-mentioned upper limit or less, low dielectric properties tend to be further improved. The total amount of the styrene compound units having a radical reactive group and the conjugated diene units contained in the elastomer (A) does not exceed 100% by mass.

[0034] In this embodiment, the elastomer (A) has at least one polymer block (a1) and may also contain a polymer block (a2) and / or a polymer block (a3). The elastomer (A) preferably contains the polymer block (a1) and the polymer block (a2), and more preferably contains all of the polymer block (a1), the polymer block (a2), and the polymer block (a3). Specific structures in the case where at least one polymer block (a1) and polymer block (a2) are contained are preferably at least one selected from the group consisting of (a2)-(a1), (a2)-(a1)-(a2), ((a2)-(a1))nX, (a2)-(a1)-(a2)-(a1), ((a1)-(a2)-(a1))nX, ((a1)-(a2))nX and ((a2)-(a1)-(a2))nX, and more preferably ((a2)-(a1))nx. Here, X is a coupling agent residue and n is 1 to 30. The coupling agent can be selected from methyltrimethoxysilane, tetramethoxysilane, divinylbenzene, dimethyl adipate, and mixtures thereof.

[0035] The elastomer (A) preferably has a maximum Tan δ peak temperature of -30 to 80°C, more preferably 0 to 80°C, as measured by dynamic mechanical analysis (DMA) at a frequency of 10 rad / s. This range tends to improve the heat resistance of the resulting cured product. The Tan δ peak temperature is measured by dynamic mechanical analysis (DMA) in accordance with ASTM 4065, using a parallel plate configuration, an angular frequency of 10 rad / s, and a temperature sweep of +2°C per minute. The Tan δ peak temperature of a rubber is the temperature at which the Tan δ peak, corresponding to the glass-to-rubber transition, reaches its maximum value. The final crossover temperature (Tcrossover) is the temperature corresponding to the transition from more elastic behavior observed in the rubbery plateau zone to more viscous behavior observed at higher temperatures. Tcrossover is the temperature at which the elastic and viscous moduli are equal, i.e., Tan δ is 1.

[0036] The elastomer (A) of this embodiment can be produced by the method described in paragraphs 0038 to 0045 and 0104 to 0107 of JP 2022-33057 A. As such a commercially available product, for example, MD3501 manufactured by Kraton Corporation can be used.

[0037] In this embodiment, the "molecular weight" of the elastomer (A) refers to the styrene equivalent molecular weight of each polymer block in kg / mol. The molecular weight can be measured, for example, by gel permeation chromatography (GPC) using a polystyrene calibration standard according to ASTM 5296. The chromatograph is calibrated using commercially available polystyrene molecular weight standards. The molecular weight of a polymer measured using GPC calibrated in this manner is the styrene equivalent molecular weight. The detector may be a combination of an ultraviolet detector and a refractive index detector. The molecular weight expressed herein is measured at the peak of the GPC trace and is generally referred to as the "peak molecular weight." The content of styrene compound units and conjugated diene compound units having radical reactive groups is calculated based on the peak molecular weight.

[0038] In this embodiment, the peak molecular weight (Mp) of the polymer block (a1) is preferably 20 kg / mol or more, more preferably 30 kg / mol or more, even more preferably 40 kg / mol or more, still more preferably 50 kg / mol or more, and is preferably 60 kg / mol or more and 200 kg / mol or less, more preferably 180 kg / mol or less, even more preferably 160 kg / mol or less, still more preferably 140 kg / mol or less, and still more preferably 120 kg / mol or less.

[0039] In the present embodiment, the peak molecular weight (Mp) of the polymer block (a2) is preferably 3 kg / mol or more, more preferably 5 kg / mol or more, and even more preferably 10 kg / mol or more. Depending on the application, etc., it may be 15 kg / mol or more or 20 kg / mol or more. Also, it is preferably 60 kg / mol or less, more preferably 50 kg / mol or less, even more preferably 45 kg / mol or less, even more preferably 40 kg / mol or less, and even more preferably 35 kg / mol or less. Depending on the application, etc., it may be 30 kg / mol or less or 20 kg / mol or less.

[0040] In this embodiment, when the elastomer (A) is hydrogenated, the RU of the hydrogenated elastomer is preferably 0 to 1.5 meq / g, more preferably 0.01 to 1.4 meq / g, and even more preferably 0.02 to 1.3 meq / g, and may be 0.05 to 1.2 meq / g, 0.1 to 1.1 meq / g, or 0.2 to 1.0 meq / g. RU refers to the amount of olefin C═C groups in the polymerized diene units in the elastomer (A) that have not been reduced after hydrogenation, expressed in milliequivalents per gram (meq / g). RU is １ It is determined from the H-NMR spectrum.

[0041] The ratio of aromatic groups having two adjacent aromatic units in a polymer block (aromatic block index) is, for example, １ It can be calculated based on the H-NMR spectrum. Specifically, it is given by the formula: aromatic blockiness index = 100 × integral 2 / integral 1, where integral 1 is the integral between 7.5 ppm and 6.0 ppm. １ It is determined by integrating the H-NMR spectrum and dividing the obtained value by "N", where "N" is the average number of protons directly bonded to the aromatic ring, for example, 5 for an unsubstituted aromatic group (phenyl ring), 4 for a monosubstituted aromatic group such as a paramethylstyryl group, and 3 for a disubstituted aromatic group such as a dimethylstyryl group. The integral 2 is １It is determined by integrating the H-NMR spectrum from the signal minimum of 6.9-6.6 ppm to 6.0 ppm and dividing by 2. In practice, integral 2 is determined by integrating the area of ​​the spectrum from the signal minimum covering the region of the steepest valley between the downfield chemical shift of 6.9-6.6 ppm and the upfield chemical shift of 6.0 ppm. When calculating the peak areas of integral 1 and integral 2, the peak areas resulting from solvent protons are not included.

[0042] In addition to the above, the elastomer (A) can be found in JP 2022-33057 A (specifically, paragraphs 0004 to 0045, paragraphs 0065 to 0073, etc.), the contents of which are included in this specification.

[0043] The content of the elastomer (A) in the resin composition of this embodiment is preferably 0.5 to 30 parts by mass per 100 parts by mass of the resin solid content in the resin composition. The content of the elastomer (A) is preferably 1 part by mass or more, more preferably 2 parts by mass or more, even more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, even more preferably 12 parts by mass or more, and is preferably 28 parts by mass or less, more preferably 25 parts by mass or less, even more preferably 20 parts by mass or less, and may be 18 parts by mass or less or 16 parts by mass or less, depending on the application. By setting the content of the elastomer (A) to the above lower limit or more, the low dielectric properties and low thermal expansion properties of the resulting cured product tend to be further improved. Furthermore, by setting the content of the elastomer (A) to the above upper limit or less, the heat resistance of the resulting cured product tends to be further improved. The resin composition of this embodiment may contain only one type of elastomer (A) or two or more types. When two or more types are contained, the total amount is preferably within the above range.

[0044] Furthermore, the mass ratio of the elastomer (A) to the thermosetting compound (B), when the total of the elastomer (A) and the thermosetting compound (B) in the resin composition is taken as 100 parts by mass, is preferably 1 part by mass or more, more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, even more preferably 15 parts by mass or more, even more preferably 20 parts by mass or more, even more preferably 25 parts by mass or more, and is preferably 50 parts by mass or less, more preferably 45 parts by mass or less, even more preferably 40 parts by mass or less, and even more preferably 35 parts by mass or less. By setting the mass ratio at or above the lower limit, the low dielectric properties and low thermal expansion properties of the resulting cured product tend to be further improved. By setting the mass ratio at or below the upper limit, the heat resistance of the resulting cured product tends to be further improved.

[0045] <Thermosetting Compound (B)> The resin composition of this embodiment contains a thermosetting compound (B). The thermosetting compound (B) is usually a thermosetting resin. In this embodiment, the thermosetting compound (B) contains a resin (E) having two or more vinylbenzyl groups at its terminals. The thermosetting compound (B) may further contain a thermosetting compound other than the resin (E) having two or more vinylbenzyl groups at its terminals. The thermosetting compound other than the resin (E) having two or more vinylbenzyl groups at its terminal preferably includes at least one selected from the group consisting of maleimide compounds, aromatic-containing resins having a terminal carbon-carbon double bond other than the resin (E) having two or more vinylbenzyl groups at their terminals, cyanate ester compounds, (meth)allyl compounds, (meth)acrylate compounds, epoxy compounds, phenol compounds, oxetane resins, benzoxazine compounds, arylcyclobutene compounds, perfluorovinyl ether resins, polyimide compounds, and compounds having a vinylene group, more preferably includes at least one selected from the group consisting of maleimide compounds and cyanate ester compounds, and even more preferably includes a maleimide compound.

[0046] The total amount of the thermosetting compounds (B) (the resin (E) having two or more vinylbenzyl groups at its terminals and the other thermosetting compounds) in the resin composition of this embodiment is preferably 1 part by mass or more, more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, even more preferably 30 parts by mass or more, even more preferably 50 parts by mass or more, even more preferably 70 parts by mass or more, and may be 90 parts by mass or more, and preferably 99 parts by mass or less, more preferably 95 parts by mass or less, and may be 90 parts by mass or less. By setting the total amount of the thermosetting compounds (B) to the above lower limit or more, heat resistance tends to be further improved. Furthermore, by setting the total amount of the thermosetting compounds (B) to the above upper limit or less, low thermal expansion tends to be further improved. The resin composition of this embodiment may contain only one type of thermosetting compound (B), or may contain two or more types. When two or more types are contained, the total amount is preferably within the above range.

[0047] An example of a blend form of the thermosetting compound (B) is one containing a resin (E) having two or more vinylbenzyl groups at its terminals and a maleimide compound. In a first embodiment of the thermosetting compound (B), the content of the maleimide compound is preferably 50 parts by mass or more, more preferably 80 parts by mass or more, and even more preferably 100 parts by mass or more, and preferably 200 parts by mass or less, and more preferably 150 parts by mass or less, per 100 parts by mass of the resin (E) having two or more vinylbenzyl groups at its terminals. In particular, it is preferred that the resin composition contains preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably 97% by mass or more of the thermosetting compound (B) contained in the resin composition be composed of a resin (E) having two or more vinylbenzyl groups at its terminals (preferably a polyphenylene ether compound having two or more vinylbenzyl groups at its terminals and / or a polymer having a structural unit represented by formula (V)) and a maleimide compound (preferably a compound represented by formula (M1) and / or a compound represented by formula (M3) described below).

[0048] In the resin composition of this embodiment, the mass ratio ((A) / (E)) of the elastomer (A) to the resin (E) having two or more vinylbenzyl groups at its terminals is preferably 0.01 to 1.1. By making the mass ratio equal to or greater than the lower limit, the low dielectric properties of the resulting cured product tend to be further improved. Furthermore, by making the mass ratio equal to or less than the upper limit, the compatibility between the elastomer (A) and the resin (E) having two or more vinylbenzyl groups at its terminals tends to be improved, and heat resistance tends to be improved. The mass ratio ((A) / (E)) of the elastomer (A) to the resin (E) having two or more vinylbenzyl groups at its terminals is preferably 0.05 or greater, more preferably 0.1 or greater, and even more preferably 0.2 or greater. Furthermore, the upper limit of the (A) / (E) ratio may be 0.9 or less, 0.7 or less, 0.5 or less, or 0.4 or less.

[0049] <<Maleimide Compound>> The resin composition of this embodiment preferably contains a maleimide compound. In this embodiment, the maleimide compound is preferably a compound having one or more (preferably two or more, more preferably 2 to 12, even more preferably 2 to 6, even more preferably 2 to 4, still more preferably 2 or 3, and even more preferably 2) maleimide groups per molecule. In this embodiment, the maleimide compound preferably includes one or more selected from the group consisting of compounds represented by formula (M0), compounds represented by formula (M1), compounds represented by formula (M2), compounds represented by formula (M3), compounds represented by formula (M4), compounds represented by formula (M5), maleimide compound (M6), maleimide compound (M7), and maleimide compound (M8). The compounds represented by formula (M0), compounds represented by formula (M1), compounds represented by formula (M2), compounds represented by formula (M3), compounds represented by formula (M4), and compounds represented by formula (M5) are preferably one or more selected from the group consisting of compounds represented by formula (M0), compounds represented by formula (M1), compounds represented by formula (M2), compounds represented by formula (M3), compounds represented by formula (M4), and compounds represented by formula (M5). It is more preferable that the maleimide compound contains one or more compounds selected from the group consisting of compounds represented by formula (M1), compounds represented by formula (M2), compounds represented by formula (M3), compounds represented by formula (M4), and compounds represented by formula (M5), and it is even more preferable that the maleimide compound contains one or more compounds selected from the group consisting of compounds represented by formula (M1), compounds represented by formula (M3), and compounds represented by formula (M5), and it is even more preferable that the maleimide compound contains a compound represented by formula (M1) and / or a compound represented by formula (M3). When used in materials for printed wiring boards (e.g., metal foil-clad laminates), etc., excellent heat resistance can be imparted.

[0050] (In formula (M0), R ５１ each independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a phenyl group; R ５２ each independently represents a hydrogen atom or a methyl group; n １ represents an integer of 1 or more. ５１are each independently preferably one selected from the group consisting of a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, an n-pentyl group, and a phenyl group, more preferably a hydrogen atom and / or a methyl group, and even more preferably a hydrogen atom. ５２ is preferably a methyl group. １ is preferably an integer of 1 to 10, more preferably an integer of 1 to 5, even more preferably an integer of 1 to 3, still more preferably 1 or 2, and even more preferably 1. Specifically, the following compounds are preferred examples of formula (M0). In the above formula, R ８ each independently represents a hydrogen atom, a methyl group, or an ethyl group, and is preferably a methyl group.

[0051] The compound represented by formula (M0) may be a single compound or a mixture of two or more compounds. Examples of the mixture include compounds such as １ a mixture of compounds with different R ５１ and / or R ５２ a mixture of compounds having different types of substituents, a mixture of compounds having different bonding positions (meta, para, or ortho positions) of the maleimide group and the oxygen atom relative to the benzene ring, and a mixture of compounds having a combination of two or more of the above differences. The same applies to the compounds represented by formulas (M1) to (M8) below.

[0052] (In formula (M1), R Ｍ１ , R Ｍ２ , R Ｍ３ , and R Ｍ４ R each independently represents a hydrogen atom or an organic group. Ｍ５ and R Ｍ６ each independently represents a hydrogen atom or an alkyl group. Ｍ represents a divalent aromatic group. A is a 4- to 6-membered alicyclic group. R Ｍ７ and R Ｍ８ are each independently an alkyl group. mx is 1 or 2, and lx is 0 or 1. R Ｍ９ and R Ｍ１０R each independently represents a hydrogen atom or an alkyl group. Ｍ１１ , R Ｍ１２ , R Ｍ１３ , and R Ｍ１４ R each independently represents a hydrogen atom or an organic group. Ｍ１５ each independently represents an alkyl group having 1 to 10 carbon atoms, an alkyloxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a halogen atom, a hydroxyl group, or a mercapto group. px represents an integer of 0 to 3. nx represents an integer of 1 to 20.

[0053] R in the formula Ｍ１ , R Ｍ２ , R Ｍ３ , and R Ｍ４ R each independently represents a hydrogen atom or an organic group. The organic group here is preferably an alkyl group, more preferably an alkyl group having 1 to 12 carbon atoms, even more preferably an alkyl group having 1 to 6 carbon atoms, and even more preferably a methyl group, an ethyl group, a propyl group, or a butyl group, with a methyl group being particularly preferred. Ｍ１ and R Ｍ３ are each independently preferably an alkyl group, more preferably a methyl group, and R Ｍ２ and R Ｍ４ is preferably a hydrogen atom. Ｍ５ and R Ｍ６ Each of Ar independently represents a hydrogen atom or an alkyl group, and an alkyl group is preferable. The alkyl group here is preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, and further preferably a methyl group, an ethyl group, a propyl group, or a butyl group, and among these, a methyl group is particularly preferable. Ｍ represents a divalent aromatic group, preferably a phenylene group, a naphthalenediyl group, a phenanthrenediyl group, or an anthracenediyl group, more preferably a phenylene group, and even more preferably an m-phenylene group. Ｍmay have a substituent, and the substituent is preferably an alkyl group, more preferably an alkyl group having 1 to 12 carbon atoms, even more preferably an alkyl group having 1 to 6 carbon atoms, still more preferably a methyl group, an ethyl group, a propyl group, or a butyl group, and particularly preferably a methyl group. Ｍ A is preferably a 4- to 6-membered alicyclic group, more preferably a 5-membered alicyclic group (preferably a group that forms an indane ring when combined with a benzene ring). Ｍ７ and R Ｍ８ are each independently an alkyl group, preferably an alkyl group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms, and particularly preferably a methyl group. mx is 1 or 2, preferably 2. lx is 0 or 1, preferably 1. R Ｍ９ and R Ｍ１０ R each independently represents a hydrogen atom or an alkyl group, with an alkyl group being more preferred. The alkyl group here is preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, further preferably a methyl group, an ethyl group, a propyl group, or a butyl group, with a methyl group being particularly preferred. Ｍ１１ , R Ｍ１２ , R Ｍ１３ , and R Ｍ１４ R each independently represents a hydrogen atom or an organic group. The organic group here is preferably an alkyl group, more preferably an alkyl group having 1 to 12 carbon atoms, even more preferably an alkyl group having 1 to 6 carbon atoms, and even more preferably a methyl group, an ethyl group, a propyl group, or a butyl group, with a methyl group being particularly preferred. Ｍ１２ and R Ｍ１３ are each independently preferably an alkyl group, more preferably a methyl group, and R Ｍ１１ and R Ｍ１４ is preferably a hydrogen atom. Ｍ１５each independently represent an alkyl group having 1 to 10 carbon atoms, an alkyloxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a halogen atom, a hydroxyl group, or a mercapto group, and is preferably an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an aryl group having 6 to 10 carbon atoms. px represents an integer of 0 to 3, preferably an integer of 0 to 2, more preferably 0 or 1, and even more preferably 0. nx represents an integer of 1 to 20. nx may be an integer of 10 or less. The resin composition of this embodiment may contain only one or more compounds represented by formula (M1) having at least different values ​​of nx. When two or more types are contained, the average value of nx (average number of repeating units) n in the compound represented by formula (M1) in the resin composition is preferably 0.92 or more, more preferably 0.95 or more, even more preferably 1.0 or more, and even more preferably 1.1 or more, in order to have a low melting point (low softening point), low melt viscosity, and excellent handleability. Furthermore, n is preferably 10.0 or less, more preferably 8.0 or less, even more preferably 7.0 or less, even more preferably 6.0 or less, and may be 5.0 or less. The same applies to formula (M1-1) described later.

[0054] The compound represented by formula (M1) is preferably a compound represented by the following formula (M1-1): (In formula (M1-1), R Ｍ２１ , R Ｍ２２ , R Ｍ２３ , and R Ｍ２４ R each independently represents a hydrogen atom or an organic group. Ｍ２５ and R Ｍ２６ R each independently represents a hydrogen atom or an alkyl group. Ｍ２７ , R Ｍ２８ , R Ｍ２９ , and R Ｍ３０ R each independently represents a hydrogen atom or an organic group. Ｍ３１ and R Ｍ３２R each independently represents a hydrogen atom or an alkyl group. Ｍ３３ , R Ｍ３４ , R Ｍ３５ , and R Ｍ３６ R each independently represents a hydrogen atom or an organic group. Ｍ３７ , R Ｍ３８ , and R Ｍ３９ each independently represents a hydrogen atom or an alkyl group; and nx represents an integer of 1 or more and 20 or less.

[0055] R in the formula Ｍ２１ , R Ｍ２２ , R Ｍ２３ , and R Ｍ２４ R each independently represents a hydrogen atom or an organic group. The organic group here is preferably an alkyl group, more preferably an alkyl group having 1 to 12 carbon atoms, even more preferably an alkyl group having 1 to 6 carbon atoms, still more preferably a methyl group, an ethyl group, a propyl group, or a butyl group, and particularly preferably a methyl group. Ｍ２１ and R Ｍ２３ is preferably an alkyl group, more preferably a methyl group, and R Ｍ２２ and R Ｍ２４ is preferably a hydrogen atom. Ｍ２５ and R Ｍ２６ R each independently represents a hydrogen atom or an alkyl group, preferably an alkyl group. The alkyl group here is preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, further preferably a methyl group, an ethyl group, a propyl group, or a butyl group, and among these, a methyl group is particularly preferred. Ｍ２７ , R Ｍ２８ , R Ｍ２９ , and R Ｍ３０ R each independently represents a hydrogen atom or an organic group, preferably a hydrogen atom. The organic group here is preferably an alkyl group, more preferably an alkyl group having 1 to 12 carbon atoms, even more preferably an alkyl group having 1 to 6 carbon atoms, still more preferably a methyl group, an ethyl group, a propyl group, or a butyl group, and particularly preferably a methyl group. Ｍ３１ and R Ｍ３２R each independently represents a hydrogen atom or an alkyl group, preferably an alkyl group, and more preferably a methyl group. The alkyl group here is preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, and further preferably a methyl group, an ethyl group, a propyl group, or a butyl group, and among these, a methyl group is particularly preferred. Ｍ３３ , R Ｍ３４ , R Ｍ３５ , and R Ｍ３６ R each independently represents a hydrogen atom or an organic group. The organic group here is preferably an alkyl group, more preferably an alkyl group having 1 to 12 carbon atoms, even more preferably an alkyl group having 1 to 6 carbon atoms, still more preferably a methyl group, an ethyl group, a propyl group, or a butyl group, and particularly preferably a methyl group. Ｍ３３ and R Ｍ３６ is preferably a hydrogen atom, and R Ｍ３４ and R Ｍ３５ is preferably an alkyl group. Ｍ３７ , R Ｍ３８ , and R Ｍ３９ each independently represents a hydrogen atom or an alkyl group, with an alkyl group being preferred. The alkyl group here is preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, further preferably a methyl group, an ethyl group, a propyl group, or a butyl group, with a methyl group being particularly preferred. nx represents an integer of 1 to 20. nx may also be an integer of 10 or less.

[0056] The compound represented by formula (M1-1) is preferably a compound represented by the following formula (M1-2): (In formula (M1-2), R Ｍ２１ , R Ｍ２２ , R Ｍ２３ , and R Ｍ２４ R each independently represents a hydrogen atom or an organic group. Ｍ２５ and R Ｍ２６ R each independently represents a hydrogen atom or an alkyl group. Ｍ２７ , R Ｍ２８ , R Ｍ２９ , and R Ｍ３０ R each independently represents a hydrogen atom or an organic group. Ｍ３１ and R Ｍ３２R each independently represents a hydrogen atom or an alkyl group. Ｍ３３ , R Ｍ３４ , R Ｍ３５ , and R Ｍ３６ R each independently represents a hydrogen atom or an organic group. Ｍ３７ , R Ｍ３８ , and R Ｍ３９ each independently represents a hydrogen atom or an alkyl group; and nx represents an integer of 1 or more and 20 or less.

[0057] In formula (M1-2), R Ｍ２１ , R Ｍ２２ , R Ｍ２３ , R Ｍ２４ , R Ｍ２５ , R Ｍ２６ , R Ｍ２７ , R Ｍ２８ , R Ｍ２９ , R Ｍ３０ , R Ｍ３１ , R Ｍ３２ , R Ｍ３３ , R Ｍ３４ , R Ｍ３５ , R Ｍ３６ , R Ｍ３７ , R Ｍ３８ , R Ｍ３９ , and nx are R in formula (M1-1), respectively. Ｍ２１ , R Ｍ２２ , R Ｍ２３ , R Ｍ２４ , R Ｍ２５ , R Ｍ２６ , R Ｍ２７ , R Ｍ２８ , R Ｍ２９ , R Ｍ３０ , R Ｍ３１ , R Ｍ３２ , R Ｍ３３ , R Ｍ３４ , R Ｍ３５ , R Ｍ３６ , R Ｍ３７ , R Ｍ３８ , R Ｍ３９ , and nx, and the preferred ranges are also the same.

[0058] The compound represented by formula (M1-1) is preferably a compound represented by the following formula (M1-3), and more preferably a compound represented by the following formula (M1-4). (In formula (M1-3), nx represents an integer of 1 or more and 20 or less.) nx may be an integer of 10 or less. (In formula (M1-4), nx represents an integer of 1 or more and 20 or less.) nx may be an integer of 10 or less.

[0059] The molecular weight of the compound represented by formula (M1) is preferably 500 or more, more preferably 600 or more, and even more preferably 700 or more. By making the molecular weight equal to or greater than the lower limit, the low dielectric properties and low water absorption of the resulting cured product tend to be further improved. Furthermore, the molecular weight of the compound represented by formula (M1) is preferably 10,000 or less, more preferably 9,000 or less, even more preferably 7,000 or less, even more preferably 5,000 or less, and even more preferably 4,000 or less. By making the molecular weight equal to or less than the upper limit, the heat resistance and handleability of the resulting cured product tend to be further improved.

[0060] For other details of the compound represented by formula (M1), please refer to the descriptions in International Publication No. 2020-217679, the contents of which are incorporated herein by reference.

[0061] (In formula (M2), R ５４ each independently represents a hydrogen atom or a methyl group; n ４ represents an integer of 1 or more. ４ is preferably an integer of 1 to 10, more preferably an integer of 1 to 5, even more preferably an integer of 1 to 3, still more preferably 1 or 2, and may be 1. In the compound represented by formula (M2), n ４ It may be, and is preferably, a mixture of compounds in which the other moieties are different. Furthermore, as described in the compound represented by formula (M0), it may be a mixture of compounds in which the other moieties are different.

[0062] (In formula (M3), R ５５ each independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a phenyl group; n ５ represents an integer of 1 or more and 10 or less.) R ５５are each independently preferably one selected from the group consisting of a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, an n-pentyl group, and a phenyl group, more preferably a hydrogen atom and / or a methyl group, and even more preferably a hydrogen atom. ５ is preferably an integer of 1 or more and 5 or less, more preferably an integer of 1 to 3, and even more preferably 1 or 2. In the compound represented by formula (M3), n ５ It may be, and is preferably, a mixture of compounds in which the other moieties are different. Furthermore, as described in the compound represented by formula (M0), it may be a mixture of compounds in which the other moieties are different.

[0063] (In formula (M4), R ５６ each independently represents a hydrogen atom, a methyl group, or an ethyl group; R ５７ each independently represents a hydrogen atom or a methyl group. An example of the compound represented by formula (M4) is ５６ are each independently a methyl group or an ethyl group, and R ５７ is a methyl group. ５６ More preferably, R is a methyl group and R is an ethyl group on each of the two benzene rings. ５６ and R ５７ is a hydrogen atom.

[0064] (In formula (M5), R ５８ each independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a phenyl group; R ５９ each independently represents a hydrogen atom or a methyl group; n ６ represents an integer of 1 or more. ５８are each independently preferably one selected from the group consisting of a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, an n-pentyl group, and a phenyl group, more preferably a hydrogen atom and / or a methyl group, and even more preferably a hydrogen atom. ５９ is preferably a methyl group. ６ is preferably an integer of 1 to 10, more preferably an integer of 1 to 5, even more preferably an integer of 1 to 3, still more preferably 1 or 2, and may be 1. In the compound represented by formula (M5), n ６ The compound represented by formula (M0) may be a mixture of compounds having different moieties, and is preferably a mixture. As described in the compound represented by formula (M0), the compound may be a mixture of compounds having different moieties.

[0065] The maleimide compound (M6) is a compound having a structure represented by formula (M6) and maleimide groups at both ends of the molecular chain. (In formula (M6), R ６１ represents a linear or branched alkylene group having 1 to 16 carbon atoms, or a linear or branched alkenylene group having 2 to 16 carbon atoms. ６２ represents a linear or branched alkylene group having 1 to 16 carbon atoms, or a linear or branched alkenylene group having 2 to 16 carbon atoms. ６３ Each independently represents a linear or branched alkyl group having 1 to 16 carbon atoms, or a linear or branched alkenyl group having 2 to 16 carbon atoms. Each n independently represents an integer of 0 to 10.) For details of the maleimide compound (M6) and a production method thereof, please refer to paragraphs 0061 to 0066 of WO 2020 / 262577, the contents of which are incorporated herein by reference.

[0066] The maleimide compound (M7) is a maleimide compound obtained by reacting raw materials (1) with an aromatic amine compound (a1) having from 1 to 3 alkyl groups on an aromatic ring, an aromatic divinyl compound (a2) having two ethenyl groups, and maleic anhydride. The maleimide compound (M7) is preferably a compound having a structure represented by formula (M7). (In the above formula (M7), R １ each independently represents an alkyl group having 1 to 10 carbon atoms; R ２ each independently represents an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms; an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms; a cycloalkyl group having 3 to 10 carbon atoms; a halogen atom; a hydroxyl group; or a mercapto group; ３ , R ４ , R ５ and R ６ each independently represents a hydrogen atom or a methyl group, and R ３ and R ４ one of which is a hydrogen atom and the other is a methyl group, and R ５ and R ６ one of which is a hydrogen atom and the other is a methyl group, １ are each independently represented by the following formula (x): (In formula (x), R ７ and R ８ each independently represents a hydrogen atom or a methyl group, and R ７ and R ８ one of which is a hydrogen atom and the other is a methyl group, and R ９ each independently represents an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms; an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms; a cycloalkyl group having 3 to 10 carbon atoms; a halogen atom; a hydroxyl group; or a mercapto group, and t represents an integer of 0 to 4. １ X per benzene ring to which １ is the average number of substitutions, and represents a number from 0 to 4, p represents an integer from 1 to 3, q ​​represents an integer from 0 to 4, and k represents an integer from 1 to 100. * represents a bonding position.)

[0067] For details of the maleimide compound (M7) used in this embodiment, please refer to the description in Japanese Patent No. 7160151, the contents of which are incorporated herein by reference.

[0068] The maleimide compound (M8) is a bismaleimide compound having a hydrocarbon group in which eight or more atoms are linearly linked, and is preferably a compound represented by formula (M8): Such maleimide compounds (M8) tend to have higher stress relaxation ability, and as a result, the thermal expansion coefficient of the resulting cured product tends to be lower, and the electrical properties such as the dielectric constant and dielectric loss tangent tend to be more excellent. (In formula (M8), R １ and R ３ each independently represents a hydrocarbon group having 8 or more atoms linked in a linear chain, R ２ each independently represents a substituted or unsubstituted cyclic hydrocarbon group having 4 to 10 atoms constituting the ring, which may contain a heteroatom, and n represents a number from 0 to 10.

[0069] In formula (M8), R １ and R ３ is an octylene group, and R ２ is preferably a cycloalkylene group having an alkyl group having 6 to 8 carbon atoms as a substituent.

[0070] For the maleimide compound (M8), the descriptions in paragraphs 0014 to 0022 of JP-A-2018-083893 and paragraphs 0012 to 0022 of JP-A-2018-090728 can be referred to, the contents of which are incorporated herein by reference.

[0071] The maleimide compound may be produced by a known method, or a commercially available product may be used. Examples of commercially available products include "BMI-80" manufactured by K.I. Chemical Industry Co., Ltd. as the compound represented by formula (M0), "NE-X-9470S" and "NE-X-9480S" manufactured by DIC Corporation as the compound represented by formula (M1), "BMI-2300" manufactured by Daiwa Kasei Kogyo Co., Ltd. as the compound represented by formula (M2), "MIR-3000-70MT" manufactured by Nippon Kayaku Co., Ltd. as the compound represented by formula (M3), and "MIR-3000-70MT" manufactured by Nippon Kayaku Co., Ltd. as the compound represented by formula (M4). Examples of compounds that can be used include "BMI-70" manufactured by K.I. Chemical Industry Co., Ltd. and "BMI-5100" manufactured by Daiwa Kasei Kogyo Co., Ltd.; examples of compounds represented by formula (M5) include "MIR-5000" manufactured by Nippon Kayaku Co., Ltd.; examples of maleimide compounds (M6) include "MIZ-001" manufactured by Nippon Kayaku Co., Ltd.; examples of maleimide compounds (M7) include "NE-X-9500" manufactured by DIC Corporation; examples of maleimide compounds (M8) include "SFR" manufactured by Resonac Inc., and "BMI-689", "BMI-3000", and "BMI-5000" manufactured by Designer Molecules Inc.

[0072] Examples of maleimide compounds other than those described above include N-phenylmaleimide, N-cyclohexylmaleimide, phenylmethane maleimide oligomers, m-phenylene bismaleimide, 2,2-bis(4-(4-maleimidophenoxy)-phenyl)propane, 4-methyl-1,3-phenylene bismaleimide, 1,6-bismaleimide-(2,2,4-trimethyl)hexane, 4,4'-diphenylether bismaleimide, 4,4'-diphenylsulfone bismaleimide, 1,3-bis(3-maleimidophenoxy)benzene, 1,3-bis(4-maleimidophenoxy)benzene, and prepolymers thereof, and prepolymers of these maleimides and amines. In addition to the above, the compounds described in paragraphs 0051 to 0068 of WO 2020 / 262577 can be referenced, the contents of which are incorporated herein by reference.

[0073] The maleimide group equivalent of the maleimide compound is preferably 130 g / eq. or more, more preferably 150 g / eq. or more, even more preferably 170 g / eq. or more, even more preferably 180 g / eq. or more, even more preferably 200 g / eq. or more, even more preferably 290 g / eq. or more, and preferably 1000 g / eq. or less, more preferably 800 g / eq. or less, even more preferably 700 g / eq. or less, even more preferably 600 g / eq. or less, and even more preferably 500 g / eq. or less. By setting it to be equal to or greater than the lower limit, the low dielectric properties (Dk and / or Df, particularly Df) of the obtained cured product tend to be better. Furthermore, by setting it to be equal to or less than the upper limit, the peel strength of the obtained cured product tends to be better.

[0074] When the resin composition of this embodiment contains a maleimide compound, the lower limit of the content thereof is preferably 1 part by mass or more, more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, and even more preferably 20 parts by mass or more, per 100 parts by mass of the resin solid content in the resin composition. Depending on the application, etc., it may be 25 parts by mass or more, 30 parts by mass or more, 33 parts by mass or more, 40 parts by mass or more, or 45 parts by mass or more. When the content of the maleimide compound is 1 part by mass or more, the flame resistance of the resulting cured product tends to be improved. Furthermore, the upper limit of the content of the maleimide compound is preferably 90 parts by mass or less, more preferably 80 parts by mass or less, even more preferably 70 parts by mass or less, even more preferably 60 parts by mass or less, and even more preferably 55 parts by mass or less, per 100 parts by mass of the resin solid content in the resin composition. Depending on the application, etc., it may be 50 parts by mass or less, 45 parts by mass or less, 40 parts by mass or less, 38 parts by mass or less, 35 parts by mass or less, or 30 parts by mass or less. When the content of the maleimide compound is 90 parts by mass or less, peel strength and low water absorption tend to be improved. The resin composition in this embodiment may contain only one type of maleimide compound or may contain two or more types. When two or more types are contained, it is preferable that the total amount is in the above range.

[0075] <<Resin (E) Having Two or More Terminal Vinylbenzyl Groups>> The resin composition of this embodiment includes a resin (E) having two or more terminal vinylbenzyl groups as the thermosetting resin (B). The resin (E) having two or more terminal vinylbenzyl groups is, for example, a compound having a terminal carbon-carbon double bond and an aromatic ring, and is a compound that cures upon heating. By using the resin (E) having two or more terminal vinylbenzyl groups in combination with the elastomer (A), the compatibility between the two is improved, and the thermal expansion coefficient of the resulting cured product can be further reduced. By having two or more terminal vinylbenzyl groups, for example, the polarity is lower compared to when the terminal is a (meth)acrylic group, and even lower dielectric properties can be achieved for the cured product. Furthermore, the amount of polymerization initiator and curing accelerator tends to be smaller than when the terminal is a (meth)acrylic group. Furthermore, the reactivity with maleimide compounds can be enhanced compared to when the terminal is a (meth)acrylic group.

[0076] Specifically, the resin (E) having two or more vinylbenzyl groups at its terminals preferably includes one or more selected from the group consisting of polyphenylene ether compounds having two or more vinylbenzyl groups at their terminals and polymers having a structural unit represented by formula (V), and more preferably includes a polyphenylene ether compound having two or more vinylbenzyl groups at its terminals.

[0077] The content of the resin (E) having two or more vinylbenzyl groups at its terminals in the resin composition of this embodiment is preferably 1 part by mass or more, more preferably 10 parts by mass or more, even more preferably 15 parts by mass or more, and even more preferably 20 parts by mass or more, per 100 parts by mass of the resin solids in the resin composition. Depending on the application, it is even more preferably 25 parts by mass or more, even more preferably 30 parts by mass or more, and is preferably 60 parts by mass or less, more preferably 55 parts by mass or less, and even more preferably 50 parts by mass or less. By setting the content of the resin (E) having two or more vinylbenzyl groups at its terminals to the above-mentioned lower limit or more, compatibility and heat resistance tend to be further improved. Furthermore, by setting the content of the resin (E) having two or more vinylbenzyl groups at its terminals to the above-mentioned upper limit or less, low thermal expansion properties tend to be further improved. The resin composition of this embodiment may contain only one type of resin (E) having two or more vinylbenzyl groups at its terminals, or may contain two or more types. When two or more types are contained, the total amount preferably falls within the above-mentioned range.

[0078] <<<<Polyphenylene Ether Compound Having Two or More Vinylbenzyl Groups at Terminals>>> The resin composition of this embodiment preferably contains a polyphenylene ether compound having two or more vinylbenzyl groups at its terminals. The polyphenylene ether compound having two or more vinylbenzyl groups at its terminals preferably contains a polyphenylene ether compound having two or more groups (preferably vinylbenzyl groups) represented by formula (Rx-1) described below at its terminals. Use of these polyphenylene ether compounds tends to more effectively improve the low dielectric properties and low water absorption of printed wiring boards and the like. These are described in detail below.

[0079] Examples of polyphenylene ether compounds having two or more vinylbenzyl groups at their terminals include compounds having a phenylene ether skeleton represented by the following formula (X1).

[0080] (In formula (X1), R ２４ , R ２５ , R２６ , and R ２７ may be the same or different and represent an alkyl group having 6 or less carbon atoms, an aryl group, a halogen atom, or a hydrogen atom.

[0081] The polyphenylene ether compound having two or more vinylbenzyl groups at its terminals is represented by the formula (X2): (In formula (X2), R ２８ , R ２９ , R ３０ , R ３４ , and R ３５ may be the same or different and represent an alkyl group having 6 or less carbon atoms or a phenyl group. ３１ , R ３２ , and R ３３ may be the same or different and are a hydrogen atom, an alkyl group having 6 or less carbon atoms, or a phenyl group.) and / or a repeating unit represented by formula (X3): (In formula (X3), R ３６ , R ３７ , R ３８ , R ３９ , R ４０ , R ４１ , R ４２ , and R ４３ may be the same or different and are a hydrogen atom, an alkyl group having 6 or less carbon atoms, or a phenyl group. -A- is a linear, branched, or cyclic divalent hydrocarbon group having 20 or less carbon atoms.

[0082] Examples of the polyphenylene ether compound having two or more vinylbenzyl groups at the terminals include polyphenylene ether compounds represented by formula (OP). (In formula (OP), X represents an aromatic group, and —(Y—O) ｎ１ - represents a polyphenylene ether structure, n1 represents an integer of 1 to 100, and n2 represents an integer of 1 to 4. Rx is a group represented by formula (Rx-1). (In formula (Rx-1), R １ , R ２ , and R ３each independently represents a hydrogen atom, an alkyl group, an alkenyl group, or an alkynyl group. * represents a bonding site with an oxygen atom. Each Mc independently represents a hydrocarbon group having 1 to 12 carbon atoms. z represents an integer of 0 to 4. r represents an integer of 0 to 6.

[0083] The aromatic group represented by X may or may not have a substituent on the benzene ring, but preferably has one. When the aromatic group has a substituent, examples thereof include the above-mentioned substituent Z, and the substituent is preferably at least one selected from the group consisting of an alkyl group having 6 or less carbon atoms, an aryl group, and a halogen atom, more preferably an alkyl group having 3 or less carbon atoms, and even more preferably a methyl group. In addition, the -(Y-O)n １ The polyphenylene ether structure represented by - may or may not have a substituent on the benzene ring, but preferably has one. When it has a substituent, examples of the substituent Z include the above-mentioned substituent Z, but it is preferably an alkyl group having 6 or less carbon atoms or a phenyl group, more preferably an alkyl group having 3 or less carbon atoms, and even more preferably a methyl group. １ and / or n ２ When n is an integer of 2 or more, １ n structural units (Y-O) and / or n ２ The n constitutional units may be the same or different. ２ is preferably 2 or more, more preferably 2.

[0084] In formula (Rx-1), R １ , R ２ , and R ３ R each independently represents a hydrogen atom, an alkyl group, an alkenyl group, or an alkynyl group. １ is preferably a hydrogen atom or an alkyl group, more preferably a hydrogen atom or a methyl group, and even more preferably a hydrogen atom. ２ and R ３ are each independently preferably a hydrogen atom or an alkyl group, more preferably a hydrogen atom or a methyl group, and even more preferably a hydrogen atom. １ , R ２ , and R３ The number of carbon atoms in each of the alkyl group, alkenyl group, and alkynyl group is preferably 5 or less, and more preferably 3 or less.

[0085] In formula (Rx-1), r represents an integer of 0 to 6, and may be an integer of 1 or more, and is preferably an integer of 5 or less, more preferably an integer of 4 or less, even more preferably an integer of 3 or less, still more preferably 1 or 2, and even more preferably 1.

[0086] In formula (Rx-1), each Mc independently represents a hydrocarbon group having 1 to 12 carbon atoms, preferably a hydrocarbon group having 1 to 10 carbon atoms, more preferably a linear or branched alkyl group having 1 to 10 carbon atoms, still more preferably a methyl group, ethyl group, isopropyl group, isobutyl group, t-butyl group, pentyl group, octyl group, or nonyl group, and even more preferably a methyl group, ethyl group, isopropyl group, isobutyl group, or t-butyl group. In formula (Rx-1), z represents an integer of 0 to 4, preferably an integer of 0 to 3, more preferably an integer of 0 to 2, still more preferably 0 or 1, and still more preferably 0.

[0087] A specific example of the group represented by formula (Rx-1) is a vinylbenzyl group.

[0088] An example of the polyphenylene ether compound having two or more vinylbenzyl groups at its terminals is a compound represented by formula (OP-1). (In formula (OP-1), X represents an aromatic group, and —(Y—O)n ２ - represents a polyphenylene ether structure, and R １ , R ２ , and R ３ each independently represents a hydrogen atom, an alkyl group, an alkenyl group, or an alkynyl group; n １ represents an integer of 0 to 6, n ２ represents an integer from 1 to 100, and n ３represents an integer of 1 to 4.) The aromatic group represented by X may or may not have a substituent on the benzene ring, but preferably has one. When the aromatic group has a substituent, examples thereof include the above-mentioned substituent Z, but it is preferably at least one selected from the group consisting of an alkyl group having 6 or less carbon atoms, an aryl group, and a halogen atom, more preferably an alkyl group having 3 or less carbon atoms, and even more preferably a methyl group. In addition, the -(Y-O)n ２ The polyphenylene ether structure represented by - may or may not have a substituent on the benzene ring, but preferably has one. When it has a substituent, examples of the substituent Z include the above-mentioned substituent Z, but it is preferably an alkyl group having 6 or less carbon atoms or a phenyl group, more preferably an alkyl group having 3 or less carbon atoms, and even more preferably a methyl group. ２ and / or n ３ When n is an integer of 2 or more, ２ n structural units (Y-O) and / or n ３ The n constitutional units may be the same or different. ３ is preferably 2 or more, more preferably 2.

[0089] In this embodiment, the polyphenylene ether compound having two or more vinylbenzyl groups at its terminals is preferably a compound represented by formula (OP-2). Here, -(O-X-O)- represents the formula (OP-3): (In formula (OP-3), R ４ , R ５ , R ６ , R １０ , and R １１ may be the same or different and are alkyl groups or phenyl groups having 6 or less carbon atoms. ７ , R ８ , and R ９ may be the same or different and are a hydrogen atom, an alkyl group having 6 or less carbon atoms, or a phenyl group.) and / or a group represented by formula (OP-4): (In formula (OP-4), R １２ , R １３ , R１４ , R １５ , R １６ , R １７ , R １８ , and R １９ may be the same or different and are a hydrogen atom, an alkyl group having 6 or less carbon atoms, or a phenyl group. -A- is a linear, branched, or cyclic divalent hydrocarbon group having 20 or less carbon atoms.

[0090] In addition, -(Y-O)- is a group represented by formula (OP-5): (In formula (OP-5), R ２０ , R ２１ may be the same or different and are alkyl groups or phenyl groups having 6 or less carbon atoms. ２２ , R ２３ may be the same or different and are a hydrogen atom, an alkyl group having 6 or less carbon atoms, or a phenyl group. ２０ and R ２１ are each independently a group having one or more methyl groups and / or cyclohexyl groups, the rigidity of the resulting resin molecules is increased, and since highly rigid molecules have lower mobility than less rigid molecules, the relaxation time during dielectric relaxation is longer, resulting in excellent low dielectric properties (Dk and / or Df, particularly Dk), which is preferable. An example of formula (OP-5) is the following structure. For the polyphenylene ether compound having the above structure, the description in JP-A-2019-194312 can be referred to, the contents of which are incorporated herein by reference.

[0091] In formula (OP-2), a and b each independently represent an integer of 0 to 100, and at least one of a and b is an integer of 1 to 100. a and b each independently represent an integer of 0 to 50, more preferably an integer of 1 to 30, and preferably an integer of 1 to 10. When a and / or b is an integer of 2 or greater, two or more -(Y-O)- groups may each independently represent an arrangement of one type of structure, or two or more types of structures may be arranged in blocks or randomly. Furthermore, when a compound represented by formula (OP-2) is contained, the average value of a preferably satisfies 1<a<10, and the average value of b preferably satisfies 1<b<10.

[0092] Examples of -A- in formula (OP-4) include divalent organic groups such as a methylene group, an ethylidene group, a 1-methylethylidene group, a 1,1-propylidene group, a 1,4-phenylenebis(1-methylethylidene) group, a 1,3-phenylenebis(1-methylethylidene) group, a cyclohexylidene group, a phenylmethylene group, a naphthylmethylene group, and a 1-phenylethylidene group, but are not limited to these.

[0093] Among the compounds represented by the above formula (OP-2), R ４ , R ５ , R ６ , R １０ , R １１ , R ２０ , and R ２１ is an alkyl group having 3 or less carbon atoms, and R ７ , R ８ , R ９ , R １２ , R １３ , R １４ , R １５ , R １６ , R １７ , R １８ , R １９ , R ２２ , and R ２３is a hydrogen atom or an alkyl group having 3 or less carbon atoms, and it is particularly preferred that -(O-X-O)- represented by formula (OP-3) or formula (OP-4) is formula (OP-9), formula (OP-10), and / or formula (OP-11), and that -(Y-O)- represented by formula (OP-5) is formula (OP-12) or formula (OP-13). When a and / or b are integers of 2 or more, the two or more -(Y-O)- may each independently be a structure in which two or more of formula (OP-12) and / or formula (OP-13) are arranged, or a structure in which formula (OP-12) and formula (OP-13) are arranged in blocks or randomly.

[0094] (In formula (OP-10), R ４４ , R ４５ , R ４６ , and R ４７ may be the same or different and are a hydrogen atom or a methyl group. -B- is a linear, branched or cyclic divalent hydrocarbon group having 20 or less carbon atoms. Specific examples of -B- include the same as the specific examples of -A- in formula (OP-4). (In formula (OP-11), -B- represents a linear, branched, or cyclic divalent hydrocarbon group having 20 or less carbon atoms.) Specific examples of -B- include the same as the specific examples of -A- in formula (OP-4).

[0095] The polyphenylene ether compound having two or more vinylbenzyl groups at its terminals is more preferably a compound represented by formula (OP-15). (In formula (OP-15), a and b each independently represent an integer of 0 to 100, and at least one of a and b is an integer of 1 to 100.) a and b in formula (OP-15) each independently have the same meanings as a and b in formula (OP-2), and the preferred ranges are also the same.

[0096] In addition, the polyphenylene ether compound having two or more vinylbenzyl groups at its terminals used in this embodiment may also be a compound represented by formula (OP-16). (In formula (OP-16), a and b each independently represent an integer of 0 to 100, and at least one of a and b is an integer of 1 to 100.) a and b in formula (OP-16) each independently have the same meanings as a and b in formula (OP-2), and the preferred ranges are also the same.

[0097] The polyphenylene ether compound having two or more vinylbenzyl groups at its terminals may be produced by a known method, or a commercially available product such as "OPE-2St1200" and "OPE-2St2200" manufactured by Mitsubishi Gas Chemical Company, Inc. may be used.

[0098] In addition, for details of the polyphenylene ether compound having two or more vinylbenzyl groups at its terminals, the descriptions in JP 2006-028111 A, JP 2018-131519 A, WO 2019-138992, and WO 2022-054303 can be referred to within the scope of the present invention, and the contents of these publications are incorporated herein by reference.

[0099] The polystyrene-equivalent number average molecular weight (GPC) of the polyphenylene ether compound having two or more vinylbenzyl groups at its terminals is preferably 500 or more and 3,000 or less (details follow the method described in the Examples below). Having a number average molecular weight of 500 or more tends to further reduce stickiness when the resin composition of the present embodiment is formed into a coating film. Furthermore, having a number average molecular weight of 3,000 or less tends to further improve solubility in solvents. Furthermore, the polystyrene-equivalent weight average molecular weight (GPC) of the polyphenylene ether compound having two or more vinylbenzyl groups at its terminals is preferably 800 or more and 10,000 or less, more preferably 800 or more and 5,000 or less (details follow the method described in the Examples below). When the weight-average molecular weight is equal to or greater than the lower limit, the dielectric constant (Dk) and dielectric dissipation factor (Df) of the cured resin composition tend to be lower. When the weight-average molecular weight is equal to or less than the upper limit, the solubility, low viscosity, and moldability of the resin composition in solvents when preparing varnishes, etc., as described below, tend to be improved. Furthermore, the terminal carbon-carbon unsaturated double bond equivalent of the polyphenylene ether compound having two or more vinylbenzyl groups at its terminals is preferably 400 to 5,000 g per carbon-carbon unsaturated double bond, and more preferably 400 to 2,500 g. When the terminal carbon-carbon unsaturated double bond equivalent is equal to or greater than the lower limit, the dielectric constant (Dk) and dielectric dissipation factor (Df) of the cured resin composition tend to be lower. When the weight-average molecular weight is equal to or less than the upper limit, the solubility, low viscosity, and moldability of the resin composition in solvents tend to be improved.

[0100] The functional group equivalent (equivalent of carbon-carbon unsaturated double bonds) in a polyphenylene ether compound having two or more vinylbenzyl groups at its terminals is calculated from the reciprocal of the amount of double bonds determined from the results of measurement using an infrared spectrometer. The double bond equivalent [g / eq.] was determined as follows: A powder of the polyphenylene ether compound is weighed and the weight is recorded. This powder is placed in a measuring flask and then diluted to a predetermined amount with carbon disulfide to prepare a measurement sample. This sample liquid is placed in a measurement cell and set in an infrared spectrophotometer (FT / IR-4600, manufactured by JASCO Corporation). Subsequently, infrared spectroscopy of the sample liquid is performed. In the case of a vinyl group in a polyphenylene ether compound, the 905 cm －１ When the carbon-carbon unsaturated double bond is a methacrylic group, the peak area of ​​the spectrum around 1640 cm is recorded. －１ The peak area of ​​the spectrum near the peak is recorded. The double bond concentration [mol / L] is calculated from this area value and the calibration curve. The double bond equivalent is then calculated using the following formula: Double bond equivalent [g / eq.] = Powder weight in measurement sample [g] / Double bond concentration [mol / L] × Measurement sample liquid volume [L]. The functional group equivalent of thermosetting compounds other than polyphenylene ether compounds having two or more vinylbenzyl groups at their terminals can also be measured using the above method. However, for compounds (monomers) that can be expressed by a single molecular weight, the value calculated by (theoretical molecular weight / number of functional groups) is used preferentially. When two or more thermosetting compounds are contained, the functional group equivalent of the thermosetting compound is the sum (weighted average) of the values ​​obtained by multiplying the functional group equivalent of each thermosetting compound by its mass fraction.

[0101] When the resin composition of this embodiment contains a polyphenylene ether compound having two or more vinylbenzyl groups at its terminals, the lower limit of the content thereof is preferably 1 part by mass or more, more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, even more preferably 15 parts by mass or more, and even more preferably 20 parts by mass or more, per 100 parts by mass of the resin solids in the resin composition, and may be 30 parts by mass or more, or 35 parts by mass or more, depending on the application, etc. By setting the content of the polyphenylene ether compound having two or more vinylbenzyl groups at its terminals to the above-mentioned lower limit or more, the moldability of the resin composition and the heat resistance, low water absorbency, and low dielectric properties (Dk and / or Df) of the obtained cured product tend to be further improved. Furthermore, the upper limit of the content of the polyphenylene ether compound having two or more vinylbenzyl groups at its terminals is preferably 90 parts by mass or less, more preferably 80 parts by mass or less, even more preferably 70 parts by mass or less, and even more preferably 60 parts by mass or less, per 100 parts by mass of the resin solids in the resin composition. Depending on the application, it may be 50 parts by mass or less, 40 parts by mass or less, or 30 parts by mass or less. By setting the content of the polyphenylene ether compound having two or more vinylbenzyl groups at its terminals to the above upper limit or less, the low dielectric properties (particularly low dielectric tangent) and chemical resistance of the obtained cured product tend to be improved. The resin composition in this embodiment may contain only one type of polyphenylene ether compound having two or more vinylbenzyl groups at its terminals, or may contain two or more types. When two or more types are contained, the total amount is preferably within the above range.

[0102] <<<Polymer Having a Structural Unit Represented by Formula (V)>>> The resin composition of the present embodiment may contain a polymer having a structural unit represented by formula (V). By containing a polymer having a structural unit represented by formula (V), a resin composition with excellent low dielectric properties (low relative dielectric constant, low dielectric loss tangent) can be obtained. (In formula (V), Ar represents an aromatic hydrocarbon linking group. * represents a bonding position.) The aromatic hydrocarbon linking group may be a group consisting only of aromatic hydrocarbons which may have a substituent, or a group consisting of a combination of aromatic hydrocarbons which may have a substituent and other linking groups, and is preferably a group consisting only of aromatic hydrocarbons which may have a substituent. Examples of the substituent that the aromatic hydrocarbon may have include the substituent Z (e.g., an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a hydroxy group, an amino group, a carboxy group, a halogen atom, etc.). It is also preferable that the aromatic hydrocarbon does not have a substituent. The aromatic hydrocarbon linking group is usually a divalent linking group.

[0103] Specific examples of the aromatic hydrocarbon linking group include a phenylene group, a naphthalenediyl group, an anthracenediyl group, a phenanthrenediyl group, a biphenyldiyl group, and a fluorenediyl group, each of which may have a substituent, and among these, a phenylene group which may have a substituent is preferred. Examples of the substituent include the above-mentioned substituent Z, but it is preferable that the above-mentioned phenylene group and other groups do not have a substituent.

[0104] It is more preferable that the polymer having a structural unit represented by formula (V) contains at least one of a structural unit represented by formula (V1) below, a structural unit represented by formula (V2) below, and a structural unit represented by formula (V3) below. In the formulas below, * represents a bonding position. Furthermore, hereinafter, the structural units represented by formulas (V1) to (V3) may be collectively referred to as "structural unit (a)."

[0105] In formulas (V1) to (V3), L １is an aromatic hydrocarbon linking group (preferably having 6 to 22 carbon atoms, more preferably 6 to 18 carbon atoms, and even more preferably 6 to 10 carbon atoms). Specific examples include phenylene groups, naphthalenediyl groups, anthracenediyl groups, phenanthrenediyl groups, biphenyldiyl groups, and fluorenediyl groups, each of which may have a substituent. Of these, phenylene groups, which may have a substituent, are preferred. Examples of substituents include the aforementioned substituent Z, but it is preferable that the aforementioned groups, such as the phenylene group, be unsubstituted. * indicates a bonding position. The compound that forms the structural unit (a) is preferably a divinyl aromatic compound, such as divinylbenzene, bis(1-methylvinyl)benzene, divinylnaphthalene, divinylanthracene, divinylbiphenyl, and divinylphenanthrene. Of these, divinylbenzene is particularly preferred. These divinyl aromatic compounds may be used alone, or two or more types may be used as necessary. That is, the structural unit (a) is preferably a structural unit derived from a divinyl aromatic compound.

[0106] As mentioned above, the polymer having the structural unit represented by formula (V) may be a homopolymer of the compound forming the structural unit (a), but may also be a copolymer with a structural unit derived from another monomer.When the polymer having the structural unit represented by formula (V) is a copolymer, its copolymerization ratio is preferably 3 mol% or more of the structural unit (a), more preferably 5 mol% or more, even more preferably 10 mol% or more, and may even be 15 mol% or more.The upper limit is preferably 90 mol% or less, more preferably 85 mol% or less, even more preferably 80 mol% or less, even more preferably 70 mol% or less, even more preferably 60 mol% or less, even more preferably 50 mol% or less, even more preferably 40 mol% or less, particularly more preferably 30 mol% or less, and may even be 25 mol% or less, 20 mol% or less.

[0107] An example of a structural unit derived from another monomer is a structural unit (b) derived from an aromatic compound having one vinyl group (monovinyl aromatic compound).

[0108] The structural unit (b) derived from a monovinyl aromatic compound is preferably a structural unit represented by the following formula (V4).

[0109] In formula (V4), L ２ is an aromatic hydrocarbon linking group, and preferred examples thereof include the above L １ Examples include the following. * indicates the bonding position. R Ｖ１ is a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms (preferably an alkyl group). Ｖ１ When R is a hydrocarbon group, it preferably has 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms. Ｖ１ and L ２ may have the above-mentioned substituent Z.

[0110] When the polymer having a structural unit represented by formula (V) is a copolymer containing a structural unit (b) derived from a monovinyl aromatic compound, examples of the monovinyl aromatic compound include vinyl aromatic compounds such as styrene, vinylnaphthalene, and vinylbiphenyl; and nuclear alkyl-substituted vinyl aromatic compounds such as o-methylstyrene, m-methylstyrene, p-methylstyrene, o,p-dimethylstyrene, o-ethylvinylbenzene, m-ethylvinylbenzene, p-ethylvinylbenzene, methylvinylbiphenyl, and ethylvinylbiphenyl. The monovinyl aromatic compounds exemplified here may optionally have the aforementioned substituent Z. Furthermore, these monovinyl aromatic compounds may be used alone or in combination with two or more. Among these, the structural unit (b) preferably contains a structural unit derived from at least one selected from the group consisting of o-ethylvinylbenzene, m-ethylvinylbenzene, and p-ethylvinylbenzene. It is more preferable that the structural unit (b) further contains a structural unit derived from styrene in addition to a structural unit derived from at least one selected from the group consisting of o-ethylvinylbenzene, m-ethylvinylbenzene, and p-ethylvinylbenzene.

[0111] When the polymer having the structural unit represented by formula (V) is a copolymer containing the structural unit (b), the copolymerization ratio of the structural unit (b) is preferably 10 mol% or more, more preferably 15 mol% or more, and may further be 20 mol% or more, 30 mol% or more, 40 mol% or more, 50 mol% or more, 60 mol% or more, 70 mol% or more, or 75 mol% or more. The upper limit is preferably 98 mol% or less, more preferably 90 mol% or less, and even more preferably 85 mol% or less.

[0112] A polymer having a structural unit represented by formula (V) may have structural units other than the structural unit (a) and the structural unit (b). Examples of such structural units include structural unit (c) derived from a cycloolefin compound. Examples of cycloolefin compounds include hydrocarbons having a double bond within the ring structure. Specific examples include monocyclic olefins such as cyclobutene, cyclopentene, cyclohexene, and cyclooctene, as well as compounds having a norbornene ring structure such as norbornene and dicyclopentadiene, and cycloolefin compounds having condensed aromatic rings such as indene and acenaphthylene. Examples of norbornene compounds include those described in paragraphs 0037 to 0043 of JP 2018-039995 A, the contents of which are incorporated herein by reference. The cycloolefin compounds exemplified here may further have the aforementioned substituent Z.

[0113] When the polymer having the structural unit represented by formula (V) is a copolymer containing the structural unit (c), the copolymerization ratio of the structural unit (c) is preferably 10 mol% or more, more preferably 20 mol% or more, and even more preferably 30 mol% or more. The upper limit is preferably 90 mol% or less, more preferably 80 mol% or less, and even more preferably 70 mol% or less, and may be 50 mol% or less, or may be 30 mol% or less.

[0114] A polymer having a structural unit represented by formula (V) may further incorporate a structural unit (d) derived from a different polymerizable compound (hereinafter also referred to as "other polymerizable compound"). Examples of other polymerizable compounds (monomers) include compounds containing three vinyl groups. Specific examples include 1,3,5-trivinylbenzene, 1,3,5-trivinylnaphthalene, and 1,2,4-trivinylcyclohexane. Alternatively, examples include ethylene glycol diacrylate, butadiene (e.g., 1,3-butadiene), and isoprene. The copolymerization ratio of the structural unit (d) derived from other polymerizable compounds is preferably 30 mol% or less, more preferably 20 mol% or less, and even more preferably 10 mol% or less.

[0115] An example of an embodiment of a polymer having a structural unit represented by formula (V) is a polymer that essentially contains the structural unit (a) and contains at least one of the structural units (b) and (c). Further, an example is an embodiment in which the total of the structural units (a) to (c) accounts for 90 mol% or more, even 95 mol% or more, and particularly 98 mol% or more of all structural units. Another example of a polymer having a structural unit represented by formula (V) is a polymer that essentially contains the structural unit (a) and contains at least one of the structural units (b) to (d). Further, an example is an embodiment in which the total of the structural units (a) to (d) accounts for 95 mol% or more, even 98 mol% or more of all structural units. Another example of a polymer having a structural unit represented by formula (V) is a polymer that essentially contains the structural unit (a), and of all structural units excluding the terminals, preferably 90 mol% or more, more preferably 95 mol% or more, and even 100 mol%. In calculating the mole percentage per total structural units, one structural unit is considered to be derived from one molecule of a monomer (e.g., a divinyl aromatic compound, a monovinyl aromatic compound, etc.) used in producing a polymer having a structural unit represented by formula (V).

[0116] The method for producing a polymer having a structural unit represented by formula (V) is not particularly limited and may be a conventional method, but examples thereof include polymerizing a raw material containing a divinyl aromatic compound (optionally in the presence of a monovinyl aromatic compound, a cycloolefin compound, etc.) in the presence of a Lewis acid catalyst. The Lewis acid catalyst may be a metal fluoride such as boron trifluoride or a complex thereof.

[0117] The structure of the chain end of the polymer having the structural unit represented by formula (V) is not particularly limited, but in terms of the group derived from the divinyl aromatic compound, it may have a structure represented by the following formula (E1). １ is the same as defined in the above formula (V1). * represents the bonding position. *-CH=CH-L １ -CH=CH ２ (E1)

[0118] When a group derived from a monovinyl aromatic compound is at the chain end, the structure may be that of the following formula (E2): ２ and R Ｖ１ are the same as defined in the formula (V4). * represents a bonding position. *-CH=CH-L ２ -R Ｖ１ (E2)

[0119] The molecular weight of the polymer having the structural unit represented by formula (V) is preferably 300 or more, more preferably 500 or more, even more preferably 1,000 or more, and even more preferably 1,500 or more, in number average molecular weight (Mn). The upper limit of the number average molecular weight is preferably 130,000 or less, more preferably 120,000 or less, even more preferably 110,000 or less, even more preferably 100,000 or less, and may be 30,000 or less, 10,000 or less, or 5,000 or less. The molecular weight of the polymer having the structural unit represented by formula (V) is preferably 3,000 or more, more preferably 5,000 or more, and even more preferably 10,000 or more, in weight average molecular weight (Mw). By setting the weight average molecular weight to the above lower limit, the excellent low dielectric properties of the polymer having the structural unit represented by formula (V), particularly Df and dielectric properties after moisture absorption, can be effectively exhibited in the cured product of the resin composition. The upper limit of the weight-average molecular weight Mw is preferably 130,000 or less, more preferably 100,000 or less, even more preferably 80,000 or less, and even more preferably 50,000 or less. By setting the weight-average molecular weight to the above upper limit or less, poor embedding tends to be less likely when the prepreg or resin sheet is laminated on a circuit-forming substrate. The monodispersity (Mw / Mn), expressed as the ratio of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn), is preferably 100 or less, more preferably 50 or less, even more preferably 20 or less, and may be 15 or less, or even 12 or less. As for the lower limit, a practical value is 1.1 or more, preferably 2.0 or more, more preferably 4 or more, even more preferably 5 or more, even more preferably 7 or more, and even more preferably 8 or more. The Mw and Mn are measured according to the description in the Examples below. When the resin composition of the present embodiment contains two or more polymers having a structural unit represented by formula (V), it is preferable that the Mw, Mn and Mw / Mn of the mixture satisfy the above ranges.

[0120] The vinyl group equivalent of the polymer having a structural unit represented by formula (V) is preferably 200 g / eq. or more, more preferably 230 g / eq. or more, even more preferably 250 g / eq. or more, and may be 300 g / eq. or more, or 350 g / eq. or more. The vinyl group equivalent is preferably 1200 g / eq. or less, more preferably 1000 g / eq. or less, and may further be 800 g / eq. or less, 600 g / eq. or less, 500 g / eq. or less, 400 g / eq. or less, or 350 g / eq. or less. When the vinyl group equivalent is above the lower limit, the storage stability of the resin composition is improved and the fluidity of the resin composition tends to be improved. Therefore, moldability is improved, voids are less likely to occur when forming a prepreg, etc., and a more reliable printed wiring board tends to be obtained. On the other hand, when the vinyl group equivalent is equal to or less than the upper limit, the heat resistance of the resulting cured product tends to be improved.

[0121] The cured product of a polymer having a structural unit represented by formula (V) preferably has excellent low dielectric properties. For example, the cured product of the polymer having the structural unit represented by formula (V) used in this embodiment preferably has a relative dielectric constant (Dk) of 2.80 or less, more preferably 2.60 or less, even more preferably 2.50 or less, and even more preferably 2.40 or less, at 10 GHz, measured according to a cavity resonator perturbation method. Furthermore, a practical lower limit of the relative dielectric constant is, for example, 1.80 or more. Furthermore, the cured product of the polymer having the structural unit represented by formula (V) preferably has a dielectric loss tangent (Df) of 0.0030 or less, more preferably 0.0020 or less, and even more preferably 0.0010 or less, at 10 GHz, measured according to a cavity resonator perturbation method. Furthermore, a practical lower limit of the dielectric loss tangent is, for example, 0.0001 or more. The relative dielectric constant (Dk) and dielectric loss tangent (Df) are measured by the following method. 4.5 g of resin powder was placed in a stainless steel mold 100 mm x 30 mm x 1.0 mm high, placed in a vacuum press (Kitagawa Seiki Co., Ltd.), and held at 200 ° C, 220 ° C, and 240 ° C for 1.5 hours, then pressed at a surface pressure of 1.9 MPa to produce a cured plate. The cured plate was then downsized to a width of 1.0 mm, dried at 120 ° C for 60 minutes, and then measured for its relative permittivity (Dk) and dielectric loss tangent (Df) at 10 GHz using a perturbation cavity resonator. The measurement temperature was 23 ° C.

[0122] For polymers having a structural unit represented by formula (V) in this specification, the compounds described in paragraphs 0029 to 0058 of WO 2017 / 115813 and their synthesis reaction conditions, etc., the compounds described in paragraphs 0013 to 0058 of JP-A 2018-039995 and their synthesis reaction conditions, etc., the compounds described in paragraphs 0008 to 0043 of JP-A 2018-168347 and their synthesis reaction conditions, etc., the compounds described in paragraphs 0014 to 0042 of JP-A 2006-070136 and their synthesis reaction conditions, etc., the compounds described in paragraphs 0014 to 0061 of JP-A 2006-089683 and their synthesis reaction conditions, etc., the compounds described in paragraphs 0008 to 0036 of JP-A 2008-248001 and their synthesis reaction conditions, etc. can be referenced, and are incorporated herein. The polymer having the structural unit represented by formula (V) may be a commercially available product, such as LF-310T50 manufactured by Nippon Steel Chemical & Material Co., Ltd.

[0123] When the resin composition of this embodiment contains a polymer having a structural unit represented by formula (V), the lower limit of its content is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and even more preferably 10 parts by mass or more, per 100 parts by mass of the resin solid content in the resin composition. Depending on the application, it may be 15 parts by mass or more, 20 parts by mass or more, 30 parts by mass or more, or 35 parts by mass or more. By setting the content of the polymer having a structural unit represented by formula (V) to the above lower limit or more, low dielectric properties, particularly a low relative dielectric constant, tend to be effectively achieved. Furthermore, the upper limit of the content of the polymer having a structural unit represented by formula (V) is preferably 90 parts by mass or less, more preferably 80 parts by mass or less, even more preferably 70 parts by mass or less, even more preferably 60 parts by mass or less, and may be 50 parts by mass or less, 40 parts by mass or less, 30 parts by mass or less, or 25 parts by mass or less, per 100 parts by mass of the resin solid content in the resin composition. By setting the content of the polymer having the structural unit represented by formula (V) to the above upper limit or less, the metal foil peel strength and low water absorption tend to be improved. The resin composition in this embodiment may contain only one type of polymer having the structural unit represented by formula (V), or may contain two or more types. When two or more types are contained, it is preferable that the total amount is within the above range. Furthermore, the resin composition in this embodiment may be configured to be substantially free of a polymer having a structural unit represented by formula (V). "Substantially free" means that the content of the polymer having the structural unit represented by formula (V) is less than 1 part by mass, preferably less than 0.1 parts by mass, and more preferably less than 0.01 parts by mass, per 100 parts by mass of the resin solid content in the resin composition.

[0124] <<Aromatic-containing resin having a carbon-carbon double bond at a terminal other than resin (E) having two or more vinylbenzyl groups at a terminal>> The resin composition of this embodiment may contain an aromatic-containing resin having a carbon-carbon double bond at a terminal other than resin (E) having two or more vinylbenzyl groups at a terminal (aromatic-containing resin having a carbon-carbon double bond at another terminal). Examples of aromatic-containing resins having a carbon-carbon double bond at another terminal include the descriptions in paragraphs 0011 to 0025 of WO 2023 / 176766, paragraphs 0012 to 0033 of WO 2023 / 176764, paragraphs 0012 to 0033 of WO 2023 / 176763, and paragraphs 0026 to 0043 of WO 2023 / 176765, the contents of which are incorporated herein by reference. Compounds represented by the following formula may also be used. (In formula (OP-14), a and b each independently represent an integer of 0 to 100, and at least one of a and b is an integer of 1 to 100.)

[0125] The resin composition of this embodiment may also be configured to be substantially free of aromatic-containing resins having other terminal carbon-carbon double bonds. Specifically, the content of aromatic-containing resins having other terminal carbon-carbon double bonds contained in the resin composition is preferably less than 10% by mass, more preferably less than 7% by mass, even more preferably less than 5% by mass, even more preferably less than 3% by mass, and may even be less than 1% by mass of the content of resin (E) having two or more terminal vinylbenzyl groups.

[0126] <<Cyanate Ester Compound>> The resin composition of this embodiment may contain a cyanate ester compound. The cyanate ester compound of this embodiment is not particularly limited as long as it contains one or more cyanate groups (cyanato groups) in one molecule (preferably two or more, more preferably 2 to 12, even more preferably 2 to 6, even more preferably 2 to 4, still more preferably 2 or 3, and even more preferably 2), and a wide variety of compounds commonly used in the field of printed wiring boards can be used. Furthermore, the cyanate ester compound is preferably a compound in which the cyanate group is directly bonded to an aromatic skeleton (aromatic ring). Preferred examples of the cyanate ester compound in this embodiment include at least one selected from the group consisting of phenol novolac-type cyanate ester compounds, naphthol aralkyl-type cyanate ester compounds (naphthol aralkyl-type cyanates), naphthylene ether-type cyanate ester compounds, biphenyl aralkyl-type cyanate ester compounds, xylene resin-type cyanate ester compounds, trisphenolmethane-type cyanate ester compounds, adamantane skeleton-type cyanate ester compounds, bisphenol M-type cyanate ester compounds, bisphenol A-type cyanate ester compounds, and diallyl bisphenol A-type cyanate ester compounds. Among these, from the viewpoint of further improving the low water absorption of the obtained cured product, at least one selected from the group consisting of phenol novolac cyanate ester compounds, naphthol aralkyl cyanate ester compounds, naphthylene ether cyanate ester compounds, xylene resin cyanate ester compounds, bisphenol M cyanate ester compounds, bisphenol A cyanate ester compounds, and diallyl bisphenol A cyanate ester compounds is more preferable, at least one selected from the group consisting of phenol novolac cyanate ester compounds and naphthol aralkyl cyanate ester compounds is even more preferable, and naphthol aralkyl cyanate ester compounds are even more preferable. These cyanate ester compounds may be prepared by known methods, or commercially available products may be used.In addition, cyanate ester compounds having a naphthol aralkyl skeleton, a naphthylene ether skeleton, a xylene skeleton, a trisphenolmethane skeleton, or an adamantane skeleton have a relatively large functional group equivalent weight and a small number of unreacted cyanate ester groups, so that cured products of resin compositions using these compounds tend to have even more excellent low water absorption. Furthermore, mainly due to the presence of an aromatic skeleton or an adamantane skeleton, plating adhesion tends to be even more improved.

[0127] As the naphthol aralkyl cyanate ester compound, a compound represented by the following formula (1) is more preferred. (In formula (1), R ３ each independently represents a hydrogen atom or a methyl group, and n3 represents an integer of 1 or greater.

[0128] In formula (1), R ３ each independently represents a hydrogen atom or a methyl group, and among these, a hydrogen atom is preferred. In formula (1), n3 represents an integer of 1 or more, preferably an integer of 1 to 20, more preferably an integer of 1 to 10, and even more preferably an integer of 1 to 6.

[0129] The novolac-type cyanate ester compound is not particularly limited, but is preferably, for example, a compound represented by the following formula (VII). (In formula (VII), R ６ each independently represents a hydrogen atom or a methyl group, and n7 represents an integer of 1 or greater.

[0130] In formula (VII), R ６ each independently represents a hydrogen atom or a methyl group, and among these, a hydrogen atom is preferable. In formula (VII), n7 represents an integer of 1 or more, preferably an integer of 1 to 20, more preferably an integer of 1 to 10, and even more preferably an integer of 1 to 6.

[0131] As the bisphenol A type cyanate ester compound, one or more compounds selected from the group consisting of 2,2-bis(4-cyanatophenyl)propane and prepolymers of 2,2-bis(4-cyanatophenyl)propane may be used.

[0132] The resin composition of this embodiment preferably contains a cyanate ester compound within a range that does not impair the effects of the present invention. When the resin composition of this embodiment contains a cyanate ester compound, the lower limit of the cyanate ester compound content is preferably 0.1 parts by mass or more, more preferably 2 parts by mass or more, even more preferably 3 parts by mass or more, and even more preferably 5 parts by mass or more, per 100 parts by mass of the resin solid content in the resin composition. When the cyanate ester compound content is 0.1 parts by mass or more, the heat resistance, flame resistance, chemical resistance, low dielectric properties (low dielectric constant, low dielectric dissipation factor), and insulating properties of the resulting cured product tend to be improved. When the resin composition of this embodiment contains a cyanate ester compound, the upper limit of the cyanate ester compound content is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, even more preferably 20 parts by mass or less, even more preferably 15 parts by mass or less, and even more preferably 10 parts by mass or less, per 100 parts by mass of the resin solid content in the resin composition. The resin composition of this embodiment may contain only one type of cyanate ester compound, or may contain two or more types of cyanate ester compounds. When two or more types are contained, the total amount is preferably within the above range.

[0133] <<(Meth)allyl Compound>> The resin composition of this embodiment may contain a (meth)allyl compound. The (meth)allyl compound preferably contains an allyl compound. The (meth)allyl compound is preferably a compound containing two or more (meth)allyl groups, more preferably a compound containing two or more allyl groups. The (meth)allyl compound preferably contains at least one selected from the group consisting of a (meth)allyl isocyanurate compound, a tri(meth)allyl cyanurate compound, a (meth)allyl group-substituted nadimide compound, a (meth)allyl compound having a glycoluril structure, and a diallyl phthalate. More preferably, the (meth)allyl compound contains at least one selected from the group consisting of a (meth)allyl isocyanurate compound, a (meth)allyl group-substituted nadimide compound, and a (meth)allyl compound having a glycoluril structure. Still more preferably, the (meth)allyl isocyanurate compound and / or a (meth)allyl group-substituted nadimide compound is further preferred. Still more preferably, the (meth)allyl group-substituted nadimide compound is further preferred.

[0134] Examples of the tri(meth)allyl cyanurate compound include tri(meth)allyl cyanurate compounds (for example, triallyl cyanurate having the structure shown below). Examples of the (meth)allyl compound include resins having an allyl group described in WO 2022 / 210095 (for example, compounds described in Synthesis Examples 3, 4, 6, 20, and 22 of the same publication), the contents of which are incorporated herein by reference.

[0135] When the resin composition of this embodiment contains a (meth)allyl compound, its molecular weight is preferably 195 or more, more preferably 300 or more, and may be 400 or more, or even 500 or more. By making the molecular weight equal to or greater than the lower limit, low dielectric properties and heat resistance tend to be further improved. The molecular weight of the (meth)allyl compound is also preferably 3000 or less, more preferably 2000 or less, even more preferably 1000 or less, and even more preferably 800 or less. By making the molecular weight equal to or less than the upper limit, low thermal expansion properties tend to be further improved.

[0136] When the resin composition of this embodiment contains a (meth)allyl compound, the content thereof is preferably 1 part by mass or more, more preferably 3 parts by mass or more, even more preferably 5 parts by mass or more, and may even be 10 parts by mass or more, per 100 parts by mass of the resin solid content in the resin composition. By setting the content of the (meth)allyl compound to be equal to or greater than the above-mentioned lower limit, excellent moldability and heat resistance tend to be further improved. Furthermore, the upper limit of the content of the (meth)allyl compound is preferably 40 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less, per 100 parts by mass of the resin solid content in the resin composition. By setting the content of the (meth)allyl compound to be equal to or less than the above-mentioned upper limit, low thermal expansion tends to be further improved. The resin composition of this embodiment may contain only one type of (meth)allyl compound, or may contain two or more types. When two or more types are contained, the total amount preferably falls within the above-mentioned range.

[0137] <<<(Meth)allyl isocyanurate compound>>> The (meth)allyl isocyanurate compound is not particularly limited as long as it is a compound having two or more (meth)allyl groups and an isocyanurate ring (nurate skeleton). Because the (meth)allyl isocyanurate compound has a large number of (meth)allyl groups that serve as crosslinking points, it tends to be firmly cured with other thermosetting compounds such as resins having two or more vinylbenzyl groups at their terminals and maleimide compounds, and to produce cured products with low dielectric properties (Dk and / or Df) and excellent heat resistance. As the (meth)allyl isocyanurate compound, a compound represented by formula (TA) is preferred. Formula (TA) (In formula (TA), R Ａ represents a substituent).

[0138] In formula (TA), R Ａ represents a substituent, and is more preferably a substituent having a formula weight of 15 to 500.

[0139] R ＡA first example is an alkyl group having 1 to 22 carbon atoms or an alkenyl group having 2 to 22 carbon atoms. By using an allyl compound having an alkyl group having 1 to 22 carbon atoms or an alkenyl group having 2 to 22 carbon atoms, a resin composition can be provided that is excellent in crosslinkability and can yield a cured product with high toughness. This can prevent cracking during etching or other processes, even when the resin composition does not contain a substrate such as glass cloth. From the viewpoint of improving handleability, the number of carbon atoms in the alkyl group and / or alkenyl group is preferably 3 or more, more preferably 8 or more, and may even be 12 or more or 18 or less. This improves the resin flow properties of the resin composition, which is believed to result in improved circuit filling properties when using the resin composition of this embodiment to fabricate a multilayer circuit board or the like.

[0140] R Ａ A second example of R is a group containing an allyl isocyanurate group. Ａ When the compound represented by formula (TA) contains an allyl isocyanurate group, the compound represented by formula (TA) is preferably a compound represented by formula (TA-1). (In formula (TA-1), R Ａ２ is a divalent linking group.

[0141] In formula (TA-1), R Ａ２ is preferably a divalent linking group having a formula weight of 54 to 250, more preferably a divalent linking group having a formula weight of 54 to 250 and both ends of which are carbon atoms, and even more preferably an aliphatic hydrocarbon group having 2 to 20 carbon atoms (however, the aliphatic hydrocarbon group may contain an ether group or may have a hydroxyl group). More specifically, R Ａ２ is preferably a group represented by any one of the following formulas (i) to (iii): (In formulas (i) to (iii), p ｃ１ represents the number of repeating methylene units and is an integer of 2 to 18. ｃ２ represents the number of repeating units of the oxyethylene group, and is 0 or 1. * represents a bonding site. ｃ１is preferably an integer of 2 to 10, more preferably an integer of 3 to 8, and even more preferably an integer of 3 to 5. ｃ２ may be 0 or 1, but is preferably 1.

[0142] R Ａ A third example is a phosphorus-based substituent.

[0143] R Ａ２ is preferably the first example.

[0144] In this embodiment, the reactive group (allyl group) equivalent of the compound represented by formula (TA) is preferably 1000 g / eq. or less. If the equivalent is 1000 g / eq. or less, it is believed that a high Tg can be more reliably obtained.

[0145] Examples of the alkyl group having 1 to 22 carbon atoms include linear or branched alkyl groups, such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, eicosyl, and docosyl groups. Examples of the alkenyl group having 2 to 22 carbon atoms include allyl and decenyl groups.

[0146] Specific examples of the compound represented by formula (TA) include triallyl isocyanurate, 5-octyl-1,3-diallyl isocyanurate, 5-dodecyl-1,3-diallyl isocyanurate, 5-tetradecyl-1,3-diallyl isocyanurate, 5-hexadecyl-1,3-diallyl isocyanurate, 5-octadecyl-1,3-diallyl isocyanurate, 5-eicosyl-1,3-diallyl isocyanurate, 5-docosyl-1,3-diallyl isocyanurate, and 5-decenyl-1,3-diallyl isocyanurate. These may be used alone or in combination of two or more, or may be used as a prepolymer.

[0147] The method for producing the compound represented by formula (TA) is not particularly limited, but for example, the compound can be obtained by reacting diallyl isocyanurate with an alkyl halide in an aprotic polar solvent such as N,N'-dimethylformamide, in the presence of a basic substance such as sodium hydroxide, potassium carbonate, or triethylamine, at a temperature of about 60°C to 150°C.

[0148] Furthermore, commercially available compounds represented by formula (TA) can also be used. Commercially available compounds include, but are not limited to, L-DAIC manufactured by Shikoku Chemical Industries Ltd., and P-DAIC having a phosphorus-based substituent manufactured by Shikoku Chemical Industries Ltd. An example of triallyl isocyanurate is TAIC manufactured by Shinryo Corporation. An example of a compound represented by formula (TA-1) is DD-1 manufactured by Shikoku Chemical Industries Ltd.

[0149] The molecular weight of the (meth)allyl isocyanurate compound (preferably a compound represented by formula (TA)) is preferably 200 or more, more preferably 300 or more, and may be 400 or more, or even 500 or more. By setting the molecular weight to be equal to or greater than the above-mentioned lower limit, the low dielectric properties (Dk and / or Df) and heat resistance of the obtained cured product tend to be further improved. Furthermore, the molecular weight of the (meth)allyl isocyanurate compound (preferably a compound represented by formula (TA)) is preferably 3000 or less, more preferably 2000 or less, even more preferably 1000 or less, and even more preferably 800 or less. By setting the molecular weight to be equal to or less than the above-mentioned upper limit, the low thermal expansion properties of the obtained cured product tend to be further improved.

[0150] When the resin composition of this embodiment contains a (meth)allyl isocyanurate compound, the content thereof is preferably 1 part by mass or more, more preferably 3 parts by mass or more, even more preferably 5 parts by mass or more, and may even be 10 parts by mass or more, per 100 parts by mass of the resin solid content in the resin composition. By setting the content of the (meth)allyl isocyanurate compound at or above the above-mentioned lower limit, the resin composition tends to have excellent moldability, and the heat resistance and low thermal expansion properties of the obtained cured product tend to be further improved. Furthermore, the upper limit of the content of the (meth)allyl isocyanurate compound is preferably 40 parts by mass or less, more preferably 30 parts by mass or less, and may even be 20 parts by mass or less, per 100 parts by mass of the resin solid content in the resin composition. By setting the content of the (meth)allyl isocyanurate compound at or below the above-mentioned upper limit, the heat resistance and low dielectric properties (Dk and / or Df) of the obtained cured product tend to be further improved. The resin composition of this embodiment may contain only one type of (meth)allyl isocyanurate compound, or may contain two or more types of (meth)allyl isocyanurate compounds. When two or more types are contained, the total amount is preferably within the above range.

[0151] <<<<(Meth)allyl Group-Substituted Nadimide Compound>>> The (meth)allyl group-substituted nadimide compound is not particularly limited as long as it is a compound having two or more (meth)allyl group-substituted nadimide groups in the molecule. Specific examples include compounds represented by the following formula (AN-1): (In formula (AN-1), R １ each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; R ２ represents an alkylene group having 1 to 6 carbon atoms, a phenylene group, a biphenylene group, a naphthylene group, or a group represented by formula (AN-2) or (AN-3). (In formula (AN-2), R ３ represents a methylene group, an isopropylidene group, —C(═O)—, —O—, —S—, or —S(═O) ２ represents a group represented by the formula: (In formula (AN-3), R ４each independently represents an alkylene group having 1 to 4 carbon atoms or a cycloalkylene group having 5 to 8 carbon atoms.

[0152] Furthermore, commercially available compounds represented by formula (AN-1) can also be used. Examples of commercially available compounds include, but are not limited to, the compound represented by formula (AN-4) (BANI-M (manufactured by Maruzen Petrochemical Co., Ltd.)) and the compound represented by formula (AN-5) (BANI-X (manufactured by Maruzen Petrochemical Co., Ltd.)). These compounds may be used alone or in combination of two or more. Formula (AN-4)

[0153] The molecular weight of the (meth)allyl group-substituted nadimide compound (preferably a compound represented by formula (AN)) is preferably 400 or more, more preferably 500 or more, and may be 550 or more. By setting the molecular weight of the (meth)allyl group-substituted nadimide compound to the above-mentioned lower limit or more, low dielectric properties, low thermal expansion, and heat resistance tend to be further improved. The molecular weight of the (meth)allyl group-substituted nadimide compound (preferably a compound represented by formula (AN)) is also preferably 1500 or less, more preferably 1000 or less, even more preferably 800 or less, and may be 700 or less, or 600 or less. By setting the molecular weight of the (meth)allyl group-substituted nadimide compound to the above-mentioned upper limit or less, moldability and peel strength tend to be further improved.

[0154] When the resin composition of the present embodiment contains a (meth)allyl group-substituted nadimide compound (preferably a compound represented by formula (AN)), the content thereof is preferably 1 part by mass or more, more preferably 3 parts by mass or more, even more preferably 5 parts by mass or more, and may even be 10 parts by mass or more, per 100 parts by mass of the resin solid content in the resin composition. By setting the content of the (meth)allyl group-substituted nadimide compound to be equal to or greater than the above-mentioned lower limit, excellent moldability and further improved low dielectric properties, low thermal expansion, and heat resistance tend to be achieved. Furthermore, the upper limit of the content of the (meth)allyl group-substituted nadimide compound (preferably a compound represented by formula (AN)) is preferably 40 parts by mass or less, more preferably 30 parts by mass or less, even more preferably 25 parts by mass or less, and may even be 20 parts by mass or less, per 100 parts by mass of the resin solid content in the resin composition. By setting the content of the (meth)allyl group-substituted nadimide compound to be equal to or less than the above-mentioned upper limit, moldability and peel strength tend to be further improved. The resin composition of the present embodiment may contain only one (meth)allyl group-substituted nadimide compound, or may contain two or more (meth)allyl group-substituted nadimide compounds. When two or more (meth)allyl group-substituted nadimide compounds are contained, the total amount is preferably in the above range.

[0155] <<<<(Meth)allyl Compound Having a Glycoluril Structure>>> The (meth)allyl compound having a glycoluril structure is not particularly limited as long as it contains a glycoluril structure and two or more (meth)allyl groups. When a (meth)allyl compound having a glycoluril structure is blended into a resin composition, the number of (meth)allyl groups can be increased, i.e., the number of crosslinking points can be increased. Therefore, similar to (meth)allyl isocyanurate compounds, it tends to be firmly cured with other thermosetting compounds such as resins having two or more vinylbenzyl groups at the terminals and maleimide compounds, and to produce cured products with low dielectric properties (Dk and / or Df) and excellent heat resistance. In this embodiment, the (meth)allyl compound having a glycoluril structure is preferably a compound represented by formula (GU). Formula (GU) (In formula (GU), R １ are each independently a hydrogen atom or a substituent, and R １At least two of R are groups containing a (meth)allyl group. ２ each independently represents a hydrogen atom, an alkyl group, or an aryl group. １ are each independently preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkenyl group having 2 to 5 carbon atoms, more preferably an alkenyl group having 2 to 5 carbon atoms, more preferably a (meth)allyl group, and even more preferably an allyl group. １ In formula (GU), it is preferable that three or four of R are groups containing a (meth)allyl group, and it is more preferable that four of R are groups containing a (meth)allyl group. ２ are each independently preferably a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group, more preferably a hydrogen atom or a methyl group, and two R ２ It is more preferable that all of are hydrogen atoms.

[0156] Specific examples of the compound represented by formula (GU) include 1,3,4,6-tetraarylglycoluril (in formula (GU), R １ are all allyl groups, and R ２ are all hydrogen atoms).

[0157] The (meth)allyl compound having a glycoluril structure may be commercially available, and examples thereof include, but are not limited to, TA-G manufactured by Shikoku Chemicals Corporation.

[0158] The molecular weight of the (meth)allyl compound having a glycoluril structure (preferably a compound represented by formula (GU)) is preferably 195 or more, more preferably 220 or more, even more preferably 250 or more, and may be 300 or more, or 400 or more. By setting the molecular weight of the (meth)allyl compound having a glycoluril structure to the above-mentioned lower limit or more, the heat resistance and low thermal expansion of the obtained cured product tend to be further improved. The molecular weight of the (meth)allyl compound having a glycoluril structure (preferably a compound represented by formula (GU)) is also preferably 1500 or less, more preferably 1000 or less, even more preferably 800 or less, and may be 700 or less, or 600 or less. By setting the molecular weight of the (meth)allyl compound having a glycoluril structure to the above-mentioned upper limit or less, the low dielectric properties (Dk and / or Df) and heat resistance of the obtained cured product tend to be further improved.

[0159] When the resin composition of the present embodiment contains a (meth)allyl compound having a glycoluril structure (preferably a compound represented by formula (GU)), the content thereof is preferably 1 part by mass or more, more preferably 3 parts by mass or more, even more preferably 5 parts by mass or more, and may even be 10 parts by mass or more, per 100 parts by mass of the resin solid content in the resin composition. By setting the content of the (meth)allyl compound having a glycoluril structure to be equal to or greater than the above-mentioned lower limit, the resin composition tends to have excellent moldability, and the heat resistance and low thermal expansion of the obtained cured product tend to be further improved. Furthermore, the upper limit of the content of the (meth)allyl compound having a glycoluril structure (preferably a compound represented by formula (GU)) is preferably 40 parts by mass or less, more preferably 30 parts by mass or less, even more preferably 25 parts by mass or less, and may even be 20 parts by mass or less, per 100 parts by mass of the resin solid content in the resin composition. By setting the content of the (meth)allyl compound having a glycoluril structure to be equal to or less than the above-mentioned upper limit, the low dielectric properties (Dk and / or Df) of the obtained cured product tend to be further improved. The resin composition of the present embodiment may contain only one (meth)allyl compound having a glycoluril structure, or may contain two or more (meth)allyl compounds. When two or more compounds are contained, the total amount is preferably in the above range.

[0160] <<<<(Meth)acrylate Compound>>> The resin composition of this embodiment may contain a (meth)acrylate compound. The (meth)acrylate compound used in this embodiment may be a monofunctional (meth)acrylate compound containing one (meth)acryloyloxy group in one molecule, or a polyfunctional (meth)acrylate compound containing two or more (meth)acryloyloxy groups in one molecule. In this embodiment, a polyfunctional (meth)acrylate compound is preferred.

[0161] The polyfunctional (meth)acrylate compound used in this embodiment is preferably a compound having three to five (meth)acryloyloxy groups, more preferably a compound having three or four (meth)acryloyloxy groups, and even more preferably a compound having three (meth)acryloyloxy groups. The (meth)acrylate compound is preferably a compound having a methacryloyloxy group. Since polyfunctional (meth)acrylate compounds have a large number of (meth)acrylate groups that serve as crosslinking points, they are firmly cured with other thermosetting compounds such as resins having two or more vinylbenzyl groups at their terminals and maleimide compounds, and a cured product with low dielectric properties (Dk and / or Df) and excellent heat resistance is obtained. The polyfunctional (meth)acrylate compound is preferably a compound represented by formula (MA). Formula (MA) (In formula (MA), R １ represents a hydrogen atom or a substituent, R ２ each independently represents a hydrogen atom or a methyl group.

[0162] In formula (MA), R １ represents a hydrogen atom or a substituent, and is more preferably a substituent having a formula weight of 15 to 500, more preferably a substituent having a formula weight of 15 to 300, even more preferably a substituent having a formula weight of 15 to 100, and even more preferably a substituent having a formula weight of 15 to 50.

[0163] R １is preferably a hydrocarbon group or a (meth)acryloyloxy group, more preferably a hydrocarbon group having 22 or fewer carbon atoms, and even more preferably an alkyl group having 1 to 22 carbon atoms or an alkenyl group having 2 to 22 carbon atoms. By using a compound having an alkyl group having 1 to 22 carbon atoms or an alkenyl group having 2 to 22 carbon atoms, a resin composition can be provided that is excellent in crosslinkability and can yield a cured product with high toughness. This can prevent cracking during etching or other processes, even when the resin composition does not contain a substrate such as glass cloth. From the viewpoint of improving handleability, the number of carbon atoms in the alkyl group and / or alkenyl group is preferably 2 or more, and may be 8 or more, or even 12 or more and 18 or less. This is thought to improve the resin flow properties of the resin composition, resulting in improved circuit filling properties when using the resin composition of this embodiment to fabricate a multilayer circuit board or the like.

[0164] In this embodiment, the (meth)acrylic group equivalent of the compound represented by formula (MA) is preferably 1000 g / eq. or less. If the equivalent is 1000 g / eq. or less, a high Tg tends to be more reliably obtained. The lower limit of the (meth)acrylic group equivalent is, for example, 99 g / eq. or more.

[0165] The alkyl group having 1 to 22 carbon atoms is preferably a linear alkyl group having 1 to 22 carbon atoms or a branched alkyl group having 3 to 22 carbon atoms, such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, a dodecyl group, a tetradecyl group, a hexadecyl group, an octadecyl group, an eicosyl group, a docosyl group, etc. The alkenyl group having 2 to 22 carbon atoms is preferably an alkenyl group having 2 to 15 carbon atoms, such as an allyl group, a decenyl group, etc.

[0166] Specific examples of the compound represented by formula (MA) include trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, pentaerythritol tetra(meth)acrylate, etc. These may be used alone or in combination of two or more, or may be used as a prepolymer.

[0167] The compound represented by formula (MA) may also be commercially available. Although there is no particular limitation on the commercially available product, an example of the commercially available product is trimethylolpropane trimethacrylate, such as "NK Ester TMPT" manufactured by Shin-Nakamura Chemical Co., Ltd.

[0168] The molecular weight of the polyfunctional (meth)acrylate compound is preferably 200 or more, more preferably 300 or more, and may be 330 or more, 400 or more, or 500 or more. By setting the molecular weight to the above-mentioned lower limit or more, the low dielectric properties (Dk and / or Df) and heat resistance of the obtained cured product tend to be further improved. Furthermore, the molecular weight of the (meth)acrylate compound (preferably a compound represented by formula (MA)) is preferably 3000 or less, more preferably 2000 or less, even more preferably 1000 or less, and even more preferably 800 or less. By setting the molecular weight to the above-mentioned upper limit or less, the low thermal expansion properties of the obtained cured product tend to be further improved.

[0169] In addition to the above, the (meth)acrylate compound may also be a resin having a (meth)acrylic group described in WO 2022 / 210095 (for example, the compounds described in Synthesis Examples 5 and 21 of the same publication) and a resin having a (meth)acrylic group described in Japanese Patent No. 6962507 (for example, the compounds described in Examples 1 to 9), or a compound described in paragraph 0049 of JP-A 2019-194312, the contents of which are incorporated herein by reference.

[0170] When the resin composition of this embodiment contains a (meth)acrylate compound, the content thereof is preferably 1 part by mass or more, more preferably 3 parts by mass or more, even more preferably 5 parts by mass or more, and may even be 10 parts by mass or more, per 100 parts by mass of the resin solid content in the resin composition. By setting the content of the (meth)acrylate compound at or above the above-mentioned lower limit, the resin composition tends to have excellent moldability, and the heat resistance and low thermal expansion properties of the obtained cured product tend to be further improved. Furthermore, the upper limit of the content of the (meth)acrylate compound is preferably 40 parts by mass or less, more preferably 30 parts by mass or less, and may even be 20 parts by mass or less, per 100 parts by mass of the resin solid content in the resin composition. By setting the content of the (meth)acrylate compound at or below the above-mentioned upper limit, the heat resistance and low dielectric properties (Dk and / or Df) of the obtained cured product tend to be further improved. The resin composition of this embodiment may contain only one type of (meth)acrylate compound, or may contain two or more types. When two or more types are contained, it is preferable that the total amount is within the above-mentioned range.

[0171] <<Epoxy Compound>> The resin composition of this embodiment may contain an epoxy compound. The epoxy compound is not particularly limited as long as it is a compound or resin having one or more epoxy groups (preferably 2 to 12, more preferably 2 to 6, even more preferably 2 to 4, still more preferably 2 or 3, and still more preferably 2) per molecule, and a wide variety of compounds commonly used in the field of printed wiring boards can be used. Examples of the epoxy compound include phenol novolac epoxy resins, bisphenol A novolac epoxy resins, glycidyl ester epoxy resins, aralkyl novolac epoxy resins, biphenyl aralkyl epoxy resins, naphthylene ether epoxy resins, cresol novolac epoxy resins, multifunctional phenol epoxy resins, naphthalene epoxy resins, anthracene epoxy resins, naphthalene skeleton-modified novolac epoxy resins, phenol aralkyl epoxy resins, naphthol aralkyl epoxy resins, dicyclopentadiene epoxy resins, biphenyl epoxy resins, alicyclic epoxy resins, polyol epoxy resins, phosphorus-containing epoxy resins, glycidyl amines, glycidyl esters, compounds in which the double bonds of butadiene or the like have been epoxidized, and compounds obtained by reacting hydroxyl group-containing silicone resins with epichlorohydrin. Use of these compounds improves the moldability and adhesion of the resin composition. Among these, from the viewpoint of further improving flame retardancy and heat resistance, the epoxy compound is preferably at least one selected from the group consisting of biphenylaralkyl epoxy resins, naphthylene ether epoxy resins, polyfunctional phenolic epoxy resins, and naphthalene epoxy resins, and more preferably a biphenylaralkyl epoxy resin.

[0172] When the resin composition of this embodiment contains an epoxy compound, the content thereof is preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 2 parts by mass or more, relative to 100 parts by mass of the resin solid content in the resin composition. When the epoxy compound content is 0.1 parts by mass or more, the metal foil peel strength and toughness tend to be improved. The upper limit of the epoxy compound content is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, even more preferably 20 parts by mass or less, and even more preferably 10 parts by mass or less, and may be 8 parts by mass or less, or 5 parts by mass or less, relative to 100 parts by mass of the resin solid content in the resin composition. When the epoxy compound content is 50 parts by mass or less, the electrical properties of the resulting cured product tend to be improved. The resin composition of this embodiment may contain only one type of epoxy compound, or may contain two or more types. When two or more types are contained, the total amount is preferably within the above range. The resin composition of this embodiment may also be configured to be substantially free of epoxy compounds. "Substantially free" means that the content of the epoxy compound is less than 0.1 parts by mass, preferably less than 0.01 parts by mass, and may even be less than 0.001 parts by mass, per 100 parts by mass of the resin solid content in the resin composition.

[0173] <<Phenol Compound>> The resin composition of this embodiment may contain a phenolic compound. The phenolic compound is not particularly limited as long as it has one or more phenolic hydroxyl groups (preferably 2 to 12, more preferably 2 to 6, even more preferably 2 to 4, even more preferably 2 or 3, and even more preferably 2) per molecule. A wide variety of compounds commonly used in the field of printed wiring boards can be used. Examples of the phenolic compound include phenol novolac resins, bisphenol A novolac phenolic resins, glycidyl ester phenolic resins, aralkyl novolac phenolic resins, biphenyl aralkyl phenolic resins, cresol novolac phenolic resins, multifunctional phenolic resins, naphthol resins, naphthol novolac resins, multifunctional naphthol resins, anthracene phenolic resins, naphthalene skeleton-modified novolac phenolic resins, phenol aralkyl phenolic resins, naphthol aralkyl phenolic resins, dicyclopentadiene phenolic resins, biphenyl phenolic resins, alicyclic phenolic resins, polyol phenolic resins, phosphorus-containing phenolic resins, and hydroxyl group-containing silicone resins. Among these, from the viewpoint of further improving the flame resistance of the resulting cured product, it is preferable to select at least one selected from the group consisting of biphenyl aralkyl phenolic resins, naphthol aralkyl phenolic resins, phosphorus-containing phenolic resins, and hydroxyl group-containing silicone resins. In addition, as for the phenolic compound, the description in paragraphs 0012 to 0025 of WO 2023 / 176765 can also be taken into consideration, and the contents thereof are incorporated herein by reference.

[0174] When the resin composition of this embodiment contains a phenolic compound, the content thereof is preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 2 parts by mass or more, per 100 parts by mass of the resin solid content in the resin composition. The content is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, even more preferably 20 parts by mass or less, still more preferably 10 parts by mass or less, and may even be 5 parts by mass or less. The resin composition of this embodiment may contain only one type of phenolic compound, or may contain two or more types. When two or more types are contained, the total amount is preferably within the above range. The resin composition of this embodiment may also be configured to be substantially free of phenolic compounds. "Substantially free" means that the content of phenolic compounds is less than 0.1 parts by mass per 100 parts by mass of the resin solid content in the resin composition.

[0175] <<Oxetane Compound>> The resin composition of this embodiment may contain an oxetane compound. The oxetane compound is not particularly limited as long as it is a compound having one or more oxetanyl groups (preferably 2 to 12, more preferably 2 to 6, even more preferably 2 to 4, even more preferably 2 or 3, and even more preferably 2), and a wide variety of compounds commonly used in the field of printed wiring boards can be used. Examples of the oxetane compound include oxetane, alkyloxetane (e.g., 2-methyloxetane, 2,2-dimethyloxetane, 3-methyloxetane, 3,3-dimethyloxetane, etc.), 3-methyl-3-methoxymethyloxetane, 3,3-di(trifluoromethyl)oxetane, 2-chloromethyloxetane, 3,3-bis(chloromethyl)oxetane, biphenyl oxetane, OXT-101 (manufactured by Toagosei Co., Ltd.), and OXT-121 (manufactured by Toagosei Co., Ltd.).

[0176] The resin composition of this embodiment preferably contains an oxetane compound to a degree that does not impair the effects of the present invention. When the resin composition of this embodiment contains an oxetane compound, the content thereof is preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 2 parts by mass or more, per 100 parts by mass of the resin solid content in the resin composition. When the content of the oxetane compound is 0.1 parts by mass or more, the metal foil peel strength and toughness of the resulting cured product tend to be improved. When the resin composition of this embodiment contains an oxetane compound, the upper limit of the content of the oxetane compound is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, even more preferably 20 parts by mass or less, even more preferably 10 parts by mass or less, and even more preferably 8 parts by mass or less, per 100 parts by mass of the resin solid content in the resin composition. When the content of the oxetane compound is 50 parts by mass or less, the electrical properties of the resulting cured product tend to be improved. The resin composition of this embodiment may contain only one oxetane compound, or may contain two or more oxetane compounds. When two or more types are contained, the total amount is preferably in the above range. Furthermore, the resin composition in this embodiment may be configured to be substantially free of oxetane compounds. "Substantially free" means that the content of the oxetane compounds is less than 0.1 parts by mass per 100 parts by mass of the resin solid content in the resin composition.

[0177] <<Benzoxazine Compound>> The resin composition of this embodiment may contain a benzoxazine compound. The benzoxazine compound is not particularly limited as long as it is a compound having two or more (preferably 2 to 12, more preferably 2 to 6, even more preferably 2 to 4, even more preferably 2 or 3, and even more preferably 2) dihydrobenzoxazine rings per molecule, and a wide variety of compounds commonly used in the field of printed wiring boards can be used. Examples of benzoxazine compounds include bisphenol A-type benzoxazine BA-BXZ (manufactured by Konishi Chemical Co., Ltd.), bisphenol F-type benzoxazine BF-BXZ (manufactured by Konishi Chemical Co., Ltd.), and bisphenol S-type benzoxazine BS-BXZ (manufactured by Konishi Chemical Co., Ltd.).

[0178] The resin composition of this embodiment preferably contains a benzoxazine compound to the extent that the effects of the present invention are not impaired. When the resin composition of this embodiment contains a benzoxazine compound, the content thereof is preferably 0.1 parts by mass or more and preferably 50 parts by mass or less per 100 parts by mass of the resin solid content in the resin composition. The resin composition of this embodiment may contain only one type of benzoxazine compound, or may contain two or more types. When two or more types are contained, it is preferable that the total amount is in the above range. Furthermore, the resin composition of this embodiment may be configured to be substantially free of a benzoxazine compound. "Substantially free" means that the content of the benzoxazine compound is less than 0.1 parts by mass per 100 parts by mass of the resin solid content in the resin composition.

[0179] <<Compound Having a Vinylene Group>> The resin composition of this embodiment may contain a compound having a vinylene group. Examples of compounds having a vinylene group include compounds containing one or more -CH=CH- groups in the molecule, and compounds containing one -CH=CH- group in the molecule are preferred. Furthermore, compounds having a vinylene group that also qualify as maleimide compounds are referred to as maleimide compounds. Specific examples of compounds having a vinylene group include preferred acenaphthylene and pyracylene, and more preferred is acenaphthylene. In this specification, compounds that also qualify as compounds having a vinylene group but are explicitly listed as components other than compounds having a vinylene group (e.g., radical polymerization initiator (C)), such as imidazole compounds described below, are not considered to be compounds having a vinylene group.

[0180] <Radical Polymerization Initiator (C)> The resin composition of this embodiment contains a radical polymerization initiator (C). By including the radical polymerization initiator (C), curing of the resin composition is further accelerated, and the solder heat resistance of the resulting cured product tends to be further improved. The type of radical polymerization initiator (C) is not particularly limited, but it is preferable that it contains at least one selected from the group consisting of imidazoles, organic metal salts, and organic peroxides, and it is more preferable that it contains an organic peroxide.More specifically, examples of the radical polymerization initiator (C) include imidazoles such as 2-ethyl-4-methylimidazole and triphenylimidazole; benzoyl peroxide, lauroyl peroxide, acetyl peroxide, parachlorobenzoyl peroxide, di-tert-butyl-di-perphthalate, α,α'-di(t-butylperoxy)diisopropylbenzene, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne-3, and di-tert-butylperoxy. organic peroxides such as oxides; azo compounds such as azobisnitriles (for example, azobisisobutyronitrile) and 2,2'-azobis(2,4,4-trimethylpentane); 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl free radical (4-hydroxy-TEMPO free radical), 2,2,6,6-tetramethylpiperidine 1-oxyl free radical (TEMPO free radical), 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxylbenzoate free radical, 1,1-diphenyl- Free radical compounds such as 2-picrylhydrazyl free radical and galvinoxyl free radical; tertiary amines such as N,N-dimethylbenzylamine, N,N-dimethylaniline, N,N-dimethyltoluidine, 2-N-ethylanilinoethanol, tri-n-butylamine, pyridine, quinoline, N-methylmorpholine, triethanolamine, triethylenediamine, tetramethylbutanediamine, and N-methylpiperidine; phenols such as phenol, xylenol, cresol, resorcinol, and catechol; Examples of suitable organic metal salts include high-temperature decomposition type radical generators such as lead-2,3-diphenylbutane; organic metal salts such as lead naphthenate, lead stearate, zinc naphthenate, zinc octoate, manganese octoate, tin oleate, dibutyltin maleate, manganese naphthenate, cobalt naphthenate, and iron acetylacetonate; compounds obtained by dissolving these organic metal salts in hydroxyl group-containing compounds such as phenol and bisphenol; inorganic metal salts such as tin chloride, zinc chloride, and aluminum chloride; and organic tin compounds such as dioctyltin oxide, other alkyl tins, and alkyl tin oxides.

[0181] The lower limit of the content of the radical polymerization initiator (C) in the resin composition of this embodiment is preferably 0.005 parts by mass or more, more preferably 0.01 parts by mass or more, and even more preferably 0.1 parts by mass or more, per 100 parts by mass of the resin solids in the resin composition. The upper limit of the content of the radical polymerization initiator (C) is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, even more preferably 3 parts by mass or less, even more preferably 2 parts by mass or less, even more preferably 1.5 parts by mass or less, even more preferably 1.0 parts by mass or less, even more preferably 0.8 parts by mass or less, and particularly preferably 0.7 parts by mass or less, per 100 parts by mass of the resin solids in the resin composition. The resin composition of this embodiment is preferable in that the resin composition can be sufficiently cured even when the content of the radical polymerization initiator (C) is 0.8 parts by mass or less. By setting the content of the radical polymerization initiator (C) within the above range, the low dielectric properties, low thermal expansion, and solder heat resistance of the resulting cured product can be further improved. The radical polymerization initiator (C) may be used alone or in combination of two or more. When two or more types are used, the total amount falls within the above range.

[0182] <Filler (D)> The resin composition of this embodiment contains a filler (D). By including the filler (D), the dielectric properties (dielectric constant and / or dielectric dissipation factor), low thermal expansion, flame resistance (solder heat resistance), and other physical properties of the resin composition and its cured product can be further improved. Furthermore, the filler (D) used in this embodiment preferably has excellent low dielectric properties (Dk and / or Df). For example, the filler (D) used in this embodiment preferably has a dielectric constant (Dk) of 8.0 or less, more preferably 6.0 or less, and even more preferably 4.0 or less at a frequency of 10 GHz measured according to a cavity resonator perturbation method. Furthermore, a practical lower limit of the dielectric constant is, for example, 2.0 or more. Furthermore, the filler (D) used in this embodiment preferably has a dielectric dissipation factor (Df) of 0.05 or less, more preferably 0.01 or less at a frequency of 10 GHz measured according to a cavity resonator perturbation method. Furthermore, the lower limit of the dielectric loss tangent is practically, for example, 0.0001 or more.

[0183] The filler (D) used in this embodiment is not particularly limited in type, and can suitably be used in the field of general use.Specifically, natural silica, fused silica, synthetic silica, amorphous silica, aerosil, hollow silica and other silica, alumina, white carbon, titanium white, titanium oxide, zinc oxide, magnesium oxide, zirconium oxide and other metal oxides, zinc borate, zinc stannate, forsterite, barium titanate, strontium titanate, calcium titanate and other composite oxides, boron nitride, aggregated boron nitride, silicon nitride, aluminum nitride and other nitrides, aluminum hydroxide, aluminum hydroxide heat treatment product (aluminum hydroxide is heat treated, and part of crystal water is reduced), boehmite, magnesium hydroxide and other metal hydroxides (including hydrates), acid Examples of fillers include molybdenum compounds such as molybdenum chloride and zinc molybdate, barium sulfate, clay, kaolin, talc, calcined clay, calcined kaolin, calcined talc, mica, E-glass, A-glass, NE-glass, NER-glass, C-glass, L-glass, D-glass, S-glass, M-glass G20, short glass fibers (including fine glass powders such as E-glass, T-glass, D-glass, S-glass, and Q-glass), hollow glass, and spherical glass, as well as organic fillers such as styrene-type, butadiene-type, and acrylic-type rubber powders, core-shell-type rubber powders, silicone resin powders, silicone rubber powders, and silicone composite powders.

[0184] In this embodiment, inorganic fillers are preferred, and more preferably contain one or more selected from the group consisting of silica, aluminum hydroxide, talc, aluminum nitride, boron nitride, forsterite, titanium oxide, barium titanate, strontium titanate, and calcium titanate. From the viewpoint of low dielectric properties (Dk and / or Df), more preferably contain one or more selected from the group consisting of silica and aluminum hydroxide, and even more preferably contain silica. By using these inorganic fillers, the properties of the cured product of the resin composition, such as dielectric properties, thermal expansion properties, heat resistance (solder heat resistance), dimensional stability, and flame retardancy, are further improved.

[0185] Among these, hollow silica is preferably included as the filler (D). Because hollow silica has a low specific gravity, even when its mass ratio relative to the resin solid content is low, it tends to be possible to further reduce the low dielectric properties (Dk and / or Df, particularly Dk) of the cured product. It also tends to improve drilling processability. Hollow silica is a particle having one or more, usually 10 or fewer, spaces inside an inorganic outer shell, and typically has 1 to 3 spaces inside the inorganic outer shell. The spaces are usually filled with vacuum or air. By including spaces not filled with silica inside the silica particles, the low dielectric properties (Dk and / or Df) of the resulting cured product are improved. Note that hollow silica is different from mesoporous silica and porous silica.

[0186] Hollow silica refers to a material containing silica as a main component, and may contain, in addition to silica, inorganic oxides such as alumina, zirconia, titania, etc. The content of silica in the hollow silica particles (A) is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more, and may be 100% by mass or less.

[0187] From the viewpoint of improving the appearance of the cured product, the hollow silica preferably has a volume average particle diameter (D50) in the range of 0.1 to 10 μm. The lower limit of the volume average particle diameter is more preferably 0.5 μm or more, even more preferably 1.0 μm or more, even more preferably 1.5 μm or more, and may even be 1.8 μm or more, or 2.0 μm or more. The upper limit of the volume average particle diameter is more preferably 5.0 μm or less, even more preferably 4.7 μm or less, and even more preferably 4.5 μm or less. The volume average particle diameter (D50) of the hollow silica can be measured by a laser diffraction / scattering method, specifically, by the method described in the Examples. Furthermore, in this embodiment, the content of particles having a particle diameter of more than 8.0 μm in the hollow silica is preferably 10 vol% or less, more preferably 5 vol% or less, and even more preferably 1 vol% or less.

[0188] The porosity of the hollow silica is preferably 5 to 80% by volume from the viewpoint of low dielectric properties and particle strength. The lower limit of the porosity is more preferably 8% by volume or more, and even more preferably 10% by volume or more. The upper limit of the porosity is more preferably 50% by volume or less, even more preferably 35% by volume or less, even more preferably 25% by volume or less, and even more preferably 20% by volume or less. Such a porosity not only provides excellent low dielectric properties (low dielectric constant and / or low dielectric dissipation factor), but also maintains particle strength at a predetermined level or higher, effectively suppressing particle cracking. The porosity of hollow silica can be calculated from particle density, specifically by the method described in the Examples.

[0189] In addition, hollow silica described in paragraphs 0008 to 0047 of Japanese Patent No. 7320692 and paragraphs 0012 to 0021 of International Publication No. 2022 / 145350 can also be used, the contents of which are incorporated herein by reference.

[0190] The content of filler (D) in the resin composition of this embodiment is 1 to 300 parts by mass per 100 parts by mass of resin solids. The content of filler (D) in the resin composition is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, even more preferably 50 parts by mass or more, even more preferably 100 parts by mass or more, and even more preferably 120 parts by mass or more, per 100 parts by mass of resin solids in the resin composition. By setting the content at or above the lower limit, the resulting cured product tends to have better low thermal expansion and low dielectric loss tangent. Furthermore, the upper limit for the content of filler (D) is preferably 280 parts by mass or less, more preferably 250 parts by mass or less, even more preferably 200 parts by mass or less, and even more preferably 180 parts by mass or less, per 100 parts by mass of resin solids in the resin composition. By setting the content at or below the upper limit, the heat resistance (solder heat resistance) of the resulting cured product and the moldability of the resin composition (suppression of void formation in the cured product) tend to be further improved. In the resin composition of this embodiment, as an example of a preferred embodiment, the content of the filler (D) is 1 to 75 mass% of the components excluding the solvent, and preferably 10 to 75 mass%. The resin composition of this embodiment may contain only one type of filler (D), or may contain two or more types. When two or more types are contained, it is preferable that the total amount is in the above range.

[0191] When the resin composition of this embodiment uses a filler (D), particularly an inorganic filler, it may further contain a silane coupling agent. The inclusion of a silane coupling agent tends to further improve the dispersibility of the filler (D) and the adhesive strength between the resin component and the filler (D) and the substrate described below. The silane coupling agent is not particularly limited, and examples thereof include silane coupling agents generally used for the surface treatment of inorganic substances, such as aminosilane compounds (e.g., γ-aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, etc.), epoxysilane compounds (e.g., γ-glycidoxypropyltrimethoxysilane, etc.), vinylsilane compounds (e.g., vinyltrimethoxysilane, vinyltriethoxysilane, tetravinylsilane, triethylvinylsilane, 1,3-vinyltetramethylsiloxane, etc.), styrylsilane compounds (e.g., 4-vinylphenyltrimethoxysilane, etc.), acrylicsilane compounds (e.g., γ-acryloxypropyltrimethoxysilane, etc.), cationic silane compounds (e.g., N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane hydrochloride, etc.), and phenylsilane compounds. Among these, it is preferable to include at least one selected from the group consisting of vinylsilane compounds, styrylsilane compounds, and acrylicsilane compounds, with vinylsilane compounds being more preferable. The silane coupling agent may be used alone or in combination of two or more. The content of the silane coupling agent is not particularly limited, but may be 0.1 to 5.0 parts by mass per 100 parts by mass of the resin solid content in the resin composition.

[0192] <Flame Retardant> The resin composition of the present embodiment may contain a flame retardant. Examples of the flame retardant include phosphorus-based flame retardants, halogen-based flame retardants, inorganic flame retardants, and silicone-based flame retardants, and phosphorus-based flame retardants are preferred. As the flame retardant, known ones can be used, for example, halogen-based flame retardants such as brominated epoxy resin, brominated polycarbonate, brominated polystyrene, brominated styrene, brominated phthalimide, tetrabromobisphenol A, pentabromobenzyl (meth)acrylate, pentabromotoluene, tribromophenol, hexabromobenzene, decabromodiphenyl ether, bis-1,2-pentabromophenylethane, chlorinated polystyrene, and chlorinated paraffin; phosphorus-containing flame retardants such as red phosphorus; tricresyl phosphate; triphenyl phosphate; 2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide; cresyl diphenyl phosphate; trixylenyl phosphate; trialkyl phosphate;

[0033] Examples of flame retardants include phosphorus-based flame retardants such as monomeric phosphate esters such as xyl phosphate and tris(chloroethyl) phosphate, phosphazenes such as phosphazene and phenoxyphosphazene, 1,3-phenylenebis(phenyl phosphate), 1,3-phenylenebis(2,6-dixylenyl phosphate), xylene bisdiphenylphosphine oxide of the bisdiphenylphosphine oxide type, condensed phosphate esters of dixylenyl phosphate, 6H-dibenz[c,e][1,2]oxaphosphorine,6,6'-[1,4-phenylenebis(methylene)]bis-,6,6'-dioxide, and condensed phosphate esters such as phosphinic acid metal salts of dialkylphosphinic acid aluminum salts of phosphinic acid salts, inorganic flame retardants, and silicone-based flame retardants. In this embodiment, among these, 1,3-phenylenebis(2,6-dixylenyl phosphate) is preferred because it does not impair the low dielectric properties (Dk and / or Df).

[0193] When the resin composition of this embodiment contains a flame retardant, the content thereof is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and even more preferably 7 parts by mass or more, per 100 parts by mass of the resin solid content in the resin composition. Depending on the application, it may be 10 parts by mass or more, 15 parts by mass or more. Furthermore, the lower limit of the content of the flame retardant is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, per 100 parts by mass of the resin solid content in the resin composition. Depending on the application, it may be 20 parts by mass or less, 15 parts by mass or less. The flame retardants can be used alone or in combination of two or more. When two or more types are used, the total amount is within the above range.

[0194] <Active ester compound> The resin composition of the present embodiment may contain an active ester compound within a range that does not impair the effects of the present invention. The active ester compound is not particularly limited, and for example, the description in paragraphs 0064 to 0066 of WO 2021 / 172317 can be referred to, the contents of which are incorporated herein by reference.

[0195] When the resin composition of this embodiment contains an active ester compound, the amount is preferably 1 part by mass or more and preferably 50 parts by mass or less per 100 parts by mass of the resin solid content in the resin composition. The resin composition of this embodiment may contain only one type of active ester compound, or may contain two or more types. When two or more types are contained, it is preferable that the total amount is in the above range. Furthermore, the resin composition of this embodiment may be configured to be substantially free of an active ester compound. "Substantially free" means that the content of the active ester compound is less than 1 part by mass, preferably less than 0.1 parts by mass, and more preferably less than 0.01 parts by mass per 100 parts by mass of the resin solid content in the resin composition.

[0196] <Dispersant> The resin composition of this embodiment may contain a dispersant. As the dispersant, those generally used for paints can be suitably used, and the type is not particularly limited. As the dispersant, a copolymer-based wetting dispersant is preferably used, and specific examples thereof include DISPERBYK (registered trademark)-110, 111, 161, 180, 2009, 2152, 2155, BYK (registered trademark)-W996, W9010, W903, and W940, manufactured by BYK Japan K.K.

[0197] When the resin composition of this embodiment contains a dispersant, the lower limit of the content is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, and may be 0.3 parts by mass or more, per 100 parts by mass of the resin solid content in the resin composition. The upper limit of the dispersant content is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and may be 3 parts by mass or less, per 100 parts by mass of the resin solid content in the resin composition. The dispersants can be used alone or in combination of two or more. When two or more types are used, the total amount falls within the above range.

[0198] <Solvent> The resin composition of this embodiment may contain a solvent, and preferably contains an organic solvent. When a solvent is contained, the resin composition of this embodiment is in a form (solution or varnish) in which at least a portion, preferably all, of the various resin solid components described above are dissolved or compatible in the solvent. The solvent is not particularly limited as long as it is a polar organic solvent or a non-polar organic solvent that can dissolve or compatible at least a portion, preferably all, of the various resin solid components described above. Examples of polar organic solvents include ketones (e.g., acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.), cellosolves (e.g., propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, etc.), esters (e.g., ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, isoamyl acetate, ethyl lactate, methyl methoxypropionate, methyl hydroxyisobutyrate, etc.), and amides (e.g., dimethoxyacetamide, dimethylformamide, etc.). Examples of non-polar organic solvents include aromatic hydrocarbons (e.g., toluene, xylene, etc.). The solvents may be used alone or in combination of two or more. When two or more solvents are used, the total amount falls within the above range.

[0199] <Other Components> In addition to the above components, the resin composition of this embodiment may contain various polymeric compounds such as thermoplastic resins and their oligomers, petroleum resins, and various additives. Examples of additives include ultraviolet absorbers, antioxidants, fluorescent brighteners, photosensitizers, dyes, pigments, thickeners, flow modifiers, lubricants, antifoaming agents, leveling agents, gloss agents, quinones, and polymerization inhibitors such as phenols, nitrosoamines, and hydroxyamines. These additives may be used alone or in combination of two or more. In the resin composition of this embodiment, the total of the elastomer (A), thermosetting compound (B), radical polymerization initiator (C), and optional flame retardant preferably accounts for 90% by mass or more, more preferably 95% by mass or more, and even more preferably 98% by mass or more of the resin solids in the resin composition.

[0200] <Applications> The resin composition of this embodiment is used as a cured product. Specifically, the resin composition of this embodiment can be suitably used as a low-dielectric-constant material and / or a low-dielectric-tangent material, such as an insulating layer for a printed wiring board, a semiconductor package material, or other electronic material resin composition. The resin composition of this embodiment can be suitably used as a material for a prepreg, a metal foil-clad laminate using a prepreg, a resin composite sheet, and a printed wiring board.

[0201] The resin composition of this embodiment preferably has a low dielectric constant (Dk) and dielectric loss tangent (Df) of the cured product. Specifically, the dielectric constant (Dk) and dielectric loss tangent (Df) of a sample obtained by removing the metal foil from a metal foil-clad laminate molded using a prepreg formed from the resin composition of this embodiment are preferably low. More specifically, the resin composition is impregnated into NE glass cloth so that the resin composition content is 70% by volume, and heated and dried at 155 ° C for 5 minutes to obtain 0.1 mm thick prepregs. Eight sheets of 12 μm thick electrolytic copper foil are placed on both sides and pressed to obtain a copper foil-clad laminate. The copper foil on both sides is removed by etching from the copper foil on both sides. The dielectric loss tangent (Df) at a frequency of 10 GHz measured by a cavity resonator perturbation method in accordance with JIS C218:2007 is preferably 0.0024 or less, more preferably 0.0021 or less. The lower limit of the dielectric loss tangent (Df) is not particularly specified, but a practical value is, for example, 0.0001 or more. Furthermore, the relative dielectric constant (Dk) at a frequency of 10 GHz measured by the cavity resonator perturbation method in accordance with JIS C218:2007 for the 0.8 mm thick sample is preferably 3.4 or less, more preferably 3.0 or less. The lower limit of the relative dielectric constant (Dk) is not particularly specified, but a practical value is, for example, 0.01 or more. Furthermore, radical curing, which can be achieved by curing a resin composition by radical curing, tends to result in rapid curing within a specific temperature range, allowing the resin composition to be cured more densely, thereby further improving the low dielectric properties (Dk and / or Df) of the resulting cured product. That is, an example of the resin composition of this embodiment is a radical-curable resin composition. More specifically, the dielectric loss tangent (Df) and relative dielectric constant (Dk) of the cured product are measured by the method described in the Examples below.

[0202] The resin composition of this embodiment also preferably has a small coefficient of thermal expansion when cured. The resin composition of this embodiment is impregnated into NE glass cloth so that the resin composition content is 70% by volume, and the resulting prepreg is heated and dried at 155 ° C. for 5 minutes to obtain a 0.1 mm thick prepreg. 12 μm thick electrolytic copper foil is placed on both sides of the resulting copper foil-clad laminate, and the copper foil on both sides is removed by etching. The resulting sample is cut (downsized) to 4.5 mm × 10 mm × 0.1 mm. The thermal expansion coefficient in the in-plane direction at 30 to 300 ° C. is preferably 7 ppm / ° C. or less, more preferably 5 ppm / ° C. or less, and practically 0 ppm / ° C. or more.

[0203] The resin composition of this embodiment is used as a layered material (including film and sheet forms) such as a prepreg or resin composite sheet that serves as an insulating layer for a printed wiring board. When used as such a layered material, the thickness is preferably 5 μm or more, more preferably 10 μm or more. The upper limit of the thickness is preferably 200 μm or less, more preferably 180 μm or less. Note that the thickness of the layered material refers to the thickness including the glass cloth, for example, when the resin composition of this embodiment is impregnated into glass cloth or the like. Materials formed from the resin composition of this embodiment may be used in applications where a pattern is formed by exposure and development, or in applications where exposure and development are not required. They are particularly suitable for applications where exposure and development are not required.

[0204] <<Prepreg>> The prepreg of this embodiment is formed from a substrate (prepreg substrate) and the resin composition of this embodiment. The prepreg of this embodiment can be obtained, for example, by applying the resin composition of this embodiment to the substrate (e.g., by impregnation and / or coating) and then semi-curing by heating (e.g., by drying at 120 to 220°C for 2 to 15 minutes). In this case, the amount of the resin composition attached to the substrate, i.e., the amount of the resin composition (including the filler (D)) relative to the total amount of the semi-cured prepreg, is preferably in the range of 20 to 99% by mass, more preferably in the range of 20 to 80% by mass.

[0205] The substrate is not particularly limited as long as it is a substrate used in various printed wiring board materials. Examples of the material of the substrate include glass fibers (e.g., E-glass, D-glass, L-glass, S-glass, T-glass, Q-glass, UN-glass, NE-glass, NER-glass, spherical glass, etc.), inorganic fibers other than glass (e.g., quartz, etc.), and organic fibers (e.g., polyimide, polyamide, polyester, liquid crystal polyester, polytetrafluoroethylene, etc.). The form of the substrate is not particularly limited, and examples include woven fabric, nonwoven fabric, roving, chopped strand mat, surfacing mat, etc. These substrates may be used alone or in combination of two or more. Among these substrates, from the viewpoint of dimensional stability, woven fabrics that have been subjected to an ultra-opening treatment and a clogging treatment are preferred. From the viewpoint of strength and low water absorption, the substrate should have a thickness of 200 μm or less and a mass of 250 g / m ２ The following glass woven fabrics are preferred, and from the viewpoint of moisture absorption and heat resistance, glass woven fabrics that have been surface-treated with epoxy silane, amino silane, or the like are preferred. From the viewpoint of electrical properties, low-dielectric glass cloths made of glass fibers exhibiting a low relative dielectric constant and low dielectric dissipation factor, such as L-glass, NE-glass, NER-glass, and Q-glass, are more preferred. Examples of substrates with a low relative dielectric constant include substrates with a relative dielectric constant of 5.0 or less (preferably, 3.0 to 4.9). Examples of substrates with a low dielectric dissipation factor include substrates with a dielectric dissipation factor of 0.006 or less (preferably, 0.001 to 0.005). The relative dielectric constant and dielectric dissipation factor are values ​​measured at a frequency of 10 GHz using a perturbation method cavity resonator.

[0206] <<Metal Foil-Clad Laminate>> The metal foil-clad laminate of this embodiment includes at least one layer formed from the prepreg of this embodiment and a metal foil disposed on one or both sides of the layer formed from the prepreg. Examples of methods for producing the metal foil-clad laminate of this embodiment include a method in which at least one prepreg of this embodiment (preferably two or more prepregs) is disposed, and a metal foil is disposed on one or both sides of the prepreg, followed by laminate molding. More specifically, the laminate can be produced by disposing a metal foil, such as copper or aluminum, on one or both sides of the prepreg and then laminating the prepreg. The number of prepregs is preferably 1 to 10, more preferably 2 to 10, and even more preferably 2 to 9. The metal foil may be any foil suitable for use in printed wiring boards, including, but not limited to, copper foils such as rolled copper foil and electrolytic copper foil. The thickness of the metal foil (preferably, copper foil) is not particularly limited and may be approximately 1.5 to 70 μm. Furthermore, when copper foil is used as the metal foil, the copper foil preferably has a surface roughness Rz of 0.2 to 4.0 μm, as measured in accordance with JIS B0601:2013. By adjusting the surface roughness Rz to 0.2 μm or more, the copper foil surface roughness becomes appropriate, and the copper foil peel strength tends to be further improved. On the other hand, by adjusting the surface roughness Rz to 4.0 μm or less, the copper foil surface roughness becomes appropriate, and the dielectric loss tangent characteristics of the resulting cured product tend to be further improved. From the viewpoint of the dielectric loss tangent characteristics and copper foil peel strength of the resulting cured product, the copper foil surface roughness Rz is more preferably 0.5 μm or more, even more preferably 0.6 μm or more, particularly preferably 0.7 μm or more, and more preferably 3.5 μm or less, even more preferably 3.0 μm or less, and particularly preferably 2.0 μm or less.

[0207] Examples of laminate molding methods include those commonly used when molding printed wiring board laminates and multilayer boards. More specifically, examples include methods using a multi-stage press, multi-stage vacuum press, continuous molding machine, autoclave molding machine, or the like, at a temperature of about 180 to 350°C, a heating time of about 100 to 300 minutes, and a surface pressure of about 1 to 10 MPa. A multilayer board can also be produced by combining the prepreg of this embodiment with a separately prepared inner layer wiring board for laminate molding. A multilayer board can be produced, for example, by placing copper foil of about 35 μm on both sides of a single prepreg of this embodiment, laminating using the molding method described above, forming an inner layer circuit, and blackening this circuit to form an inner layer circuit board. Then, this inner layer circuit board and the prepreg of this embodiment are alternately arranged one by one, and copper foil is placed on the outermost layer. This laminate molding can be carried out under the above conditions, preferably under vacuum, to produce a multilayer board. The metal foil-clad laminate of this embodiment can be suitably used as a printed wiring board.

[0208] The metal foil-clad laminate of this embodiment preferably has a peel strength of 0.30 kN / m or more, more preferably 0.35 kN / m or more, and even more preferably 0.50 kN / m or more, measured in accordance with the provisions of 5.7 "Peel Strength" of JIS C6481. There is no particular upper limit to the peel strength, but even if it is 2.00 kN / m or less, the required performance is sufficiently met.

[0209] As described above, the resin composition for electronic materials obtained using the resin composition of the present embodiment (a resin composition including a combination of specific components) can produce a cured product that has low dielectric properties (low dielectric constant, low dielectric dissipation factor), low thermal expansion, heat resistance, and excellent appearance of the cured product, as well as excellent properties such as moisture absorption and heat resistance, peel strength against metal foil, desmear resistance, crack resistance, and high-density processability.

[0210] <<Printed Wiring Board>> The printed wiring board of this embodiment includes an insulating layer and a conductor layer disposed on the surface of the insulating layer, wherein the insulating layer includes at least one of a layer formed from the resin composition of this embodiment and a layer formed from the prepreg of this embodiment. Such a printed wiring board can be manufactured using conventional methods, and the manufacturing method is not particularly limited. An example of a method for manufacturing a printed wiring board is described below. First, a metal foil-clad laminate, such as the copper foil-clad laminate described above, is prepared. Next, the surface of the metal foil-clad laminate is etched to form an inner layer circuit, thereby producing an inner layer substrate. If necessary, the surface of the inner layer circuit of this inner layer substrate is subjected to a surface treatment to increase adhesive strength. Next, a required number of the prepregs described above are stacked on the surface of the inner layer circuit, and metal foil for an outer layer circuit is further laminated on the outside, followed by heating and pressurizing to form an integral mold. In this way, a multilayer laminate is manufactured, in which an insulating layer composed of a substrate and a cured product of the resin composition is formed between the inner layer circuit and the metal foil for the outer layer circuit. Next, this multilayer laminate is subjected to hole drilling for through holes or via holes, and then a plated metal film that connects the inner layer circuit and the metal foil for the outer layer circuit is formed on the wall surface of the hole, and the metal foil for the outer layer circuit is further etched to form the outer layer circuit, thereby producing a printed wiring board.

[0211] The printed wiring board obtained in the above manufacturing example has an insulating layer and a conductor layer formed on the surface of this insulating layer, and the insulating layer contains the resin composition of the present embodiment described above and / or its cured product. That is, the prepreg of the present embodiment described above (for example, a prepreg formed from a base material and the resin composition of the present embodiment impregnated or applied thereto), or the layer formed from the resin composition of the metal foil-clad laminate of the present embodiment described above, serves as the insulating layer of the present embodiment. This embodiment also relates to a semiconductor device including the printed wiring board. For details of the semiconductor device, please refer to paragraphs 0200 to 0202 of JP 2021-021027 A, the contents of which are incorporated herein by reference.

[0212] Furthermore, it is preferable that the insulating layer formed from the cured product of the resin composition of this embodiment has a small surface roughness after roughening treatment. Specifically, the arithmetic mean roughness Ra of the surface of the insulating layer after roughening treatment is preferably 200 nm or less, more preferably 150 nm or less, and particularly preferably 100 nm or less. The lower limit of the arithmetic mean roughness Ra is not particularly limited, but may be, for example, 10 nm or more. The arithmetic mean roughness Ra of the surface of the insulating layer is measured using a non-contact surface roughness meter in VSI mode with a 50x magnification lens. The non-contact surface roughness meter used is a WYKONT3300 manufactured by Veeco Instruments.

[0213] <<Resin Composite Sheet>> The resin composite sheet of this embodiment includes a support and a layer formed from the resin composition of this embodiment and disposed on the surface of the support. The resin composite sheet can be used as a build-up film or a dry film solder resist. There are no particular limitations on the method for producing the resin composite sheet, but examples include a method of obtaining a resin composite sheet by applying (coating) a solution obtained by dissolving the resin composition of this embodiment in a solvent to a support and drying the applied solution.

[0214] Examples of the support used here include, but are not limited to, polyethylene film, polypropylene film, polycarbonate film, polyethylene terephthalate film, ethylene tetrafluoroethylene copolymer film, and release films obtained by applying a release agent to the surface of these films, organic film substrates such as polyimide film, conductive foils such as copper foil and aluminum foil, glass plates, SUS (Steel Use Stainless) plates, FRP (Fiber-Reinforced Plastics), and other plate-shaped materials.

[0215] Examples of application methods (coating methods) include methods in which a solution of the resin composition of this embodiment dissolved in a solvent is applied to a support using a bar coater, die coater, doctor blade, baker applicator, or the like. Furthermore, after drying, a single-layer sheet can be obtained by peeling or etching the support from a resin composite sheet in which the support and the resin composition are laminated. It should be noted that a single-layer sheet can also be obtained without using a support by supplying a solution of the resin composition of this embodiment dissolved in a solvent into a mold having a sheet-shaped cavity and drying it to form it into a sheet.

[0216] In the production of the monolayer sheet or resin composite sheet of this embodiment, the drying conditions for removing the solvent are not particularly limited. However, because low temperatures tend to leave the solvent in the resin composition, and high temperatures accelerate curing of the resin composition, drying conditions of 20°C to 200°C for 1 to 90 minutes are preferred. The monolayer sheet or resin composite sheet can be used in an uncured state after the solvent has been dried, or it can be used in a semi-cured (B-staged) state as needed. Furthermore, the thickness of the resin layer in the monolayer sheet or resin composite sheet of this embodiment can be adjusted by the concentration and coating thickness of the solution of the resin composition of this embodiment used for coating (coating). While not particularly limited, a thickness of 0.1 to 500 μm is preferred because a thicker coating thickness generally leads to more solvent remaining during drying.

[0217] The present invention will be explained in more detail below with reference to examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below. If the measuring instruments used in the examples are difficult to obtain due to discontinuation or the like, measurements can be made using other instruments with equivalent performance.

[0218] <Measurement of Weight-Average Molecular Weight and Number-Average Molecular Weight> The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of compounds (including resins) were measured by gel permeation chromatography (GPC) using a liquid pump (Shimadzu Corporation, LC-20AD), a differential refractive index detector (Shimadzu Corporation, RID-20A), and GPC columns (Showa Denko K.K., GPC KF-801, 802, 803, 804), with tetrahydrofuran as the solvent, a flow rate of 1.0 mL / min, and a column temperature of 40°C, using a calibration curve prepared using monodisperse polystyrene.

[0219] <Measurement of the average particle size (D50) of hollow silica> Measurement was carried out by a laser diffraction / scattering method using a laser micronsizer (LMS-3000) manufactured by Seishin Enterprise Co., Ltd., in a dry state.

[0220] <Particle density of hollow silica> Measured by gas pycnometer method. Particle density was measured using an Ultrapyc 1200e manufactured by Quantachrome Instruments. Nitrogen gas was used. <Porosity of hollow silica> Calculated from the above particle density. Specifically, the porosity was calculated using the following formula (1) assuming that the density of silica = 2.2 g / cm3. Porosity (%) = [2.2 - (particle density of hollow silica)] / 2.2 × 100 ... formula (1)

[0221] Synthesis Example 1: Synthesis of polyphenylene ether compound (B1) having terminal carbon-carbon unsaturated double bonds (two or more terminal vinylbenzyl groups) Synthesis of bifunctional phenylene ether oligomer CuBr was placed in a vertical reactor equipped with a stirrer, a thermometer, an air inlet tube, and a baffle. ２0.33 g (1.5 mmol) of copper bromide, 0.63 g (3.7 mmol) of N,N'-di-t-butylethylenediamine, 6.95 g (69 mmol) of n-butyldimethylamine, 670 g of toluene, and 320 g of methanol were charged and dissolved by stirring at a reaction temperature of 40°C. Separately, in advance, 46.2 g (171 mmol) of 2,2',3,3',5,5'-hexamethyl-(1,1'-biphenyl)-4,4'-diol, 129.5 g (1,060 mmol) of 2,6-dimethylphenol, and CuBr were added to a separate vessel. ２ 0.33 g (1.5 mmol) of copper bromide, 0.63 g (3.7 mmol) of N,N'-di-t-butylethylenediamine, 6.95 g (69 mmol) of n-butyldimethylamine, 440 g of toluene, and 170 g of methanol were charged and dissolved with stirring at a reaction temperature of 40°C. Subsequently, while bubbling a mixed gas adjusted to an oxygen concentration of 8% by mixing nitrogen and air into the mixed solution in the polymerization tank, the mixed solution in the dropping tank was added dropwise over 280 minutes and stirred. After completion of the dropwise addition, 700 g of water in which 7.1 g (16 mmol) of tetrasodium ethylenediaminetetraacetate had been dissolved was added to terminate the reaction. The aqueous layer and the organic layer were separated, and the organic layer was washed with a 1 M aqueous hydrochloric acid solution and then with pure water. The resulting solution was concentrated to 50% by mass using an evaporator, yielding 340 g of phenylene ether resin toluene solution A. The number average molecular weight as calculated on a polystyrene basis by the GPC method was 985, the weight average molecular weight as calculated on a polystyrene basis by the GPC method was 1090, and the hydroxyl equivalent was 478 g / eq.

[0222] <<Synthesis of Polyphenylene Ether Compound Having Terminal Carbon-Carbon Unsaturated Double Bonds>> A reactor equipped with a stirrer, thermometer, and reflux condenser was charged with 300 g of the toluene solution A of the phenylene ether resin obtained above, 57.5 g (0.38 mol) of vinylbenzyl chloride (manufactured by AGC Seimi Chemical Co., Ltd., "CMS-P"), 1,200 g of methylene chloride, 5 g (0.037 mol) of benzyldimethylamine, 70 g of pure water, and 63 g of a 30.5% by mass aqueous NaOH solution, and the mixture was stirred at a reaction temperature of 40°C. After stirring for 24 hours, the organic layer was washed with a 1 M aqueous hydrochloric acid solution and then with pure water. The resulting solution was concentrated and added dropwise to methanol to solidify. The solid was collected by filtration and dried in vacuo to obtain 178 g of a polyphenylene ether compound (B1) mainly composed of a compound represented by formula (OP-15). The number average molecular weight (GPC) was 1,200 in terms of polystyrene, the weight average molecular weight (GPC) was 1,840 in terms of polystyrene, the vinyl double bond equivalent was 620 g / eq., and the hydroxyl equivalent was 48,500 g / eq.

[0223] Synthesis Example 2: Synthesis of polymer (va) having structural units represented by formula (V) 2.25 moles (292.9 g) of divinylbenzene, 1.32 moles (172.0 g) of ethylvinylbenzene, 11.43 moles (1190.3 g) of styrene, and 15.0 moles (1532.0 g) of n-propyl acetate were charged into a reactor, and 600 mmol of a boron trifluoride diethyl ether complex was added at 70°C, followed by a reaction for 4 hours. The polymerization reaction was terminated with an aqueous sodium bicarbonate solution, and the oil layer was washed three times with pure water. The mixture was then subjected to reduced pressure devolatilization at 60°C, and polymer (va) having structural units represented by formula (V) was recovered. The obtained polymer (va) having structural units represented by formula (V) was weighed, and it was confirmed that 860.8 g of polymer (va) having structural units represented by formula (V) was obtained.

[0224] The resulting polymer (va) having a structural unit represented by formula (V) had a number average molecular weight Mn of 2,060, a weight average molecular weight Mw of 30,700, and a monodispersity index Mw / Mn of 14.9. １３ C-NMR and １By performing H-NMR analysis, resonance lines derived from each monomer unit used as a raw material were observed in polymer (va) having a structural unit represented by formula (V). Based on the NMR measurement results and GC analysis results, the content of each monomer unit (structural unit derived from each raw material) in polymer (va) having a structural unit represented by formula (V) was calculated as follows: structural units derived from divinylbenzene: 20.9 mol% (24.3 mass%), structural units derived from ethylvinylbenzene: 9.1 mol% (10.7 mass%), structural units derived from styrene: 70.0 mol% (65.0 mass%). In addition, the content of structural units having residual vinyl groups derived from divinylbenzene was 16.7 mol% (18.5 mass%). The vinyl group equivalent was 241 g / eq.

[0225] Example 1 15 parts by mass of elastomer (A1) (MD3501, manufactured by Kraton Chemical Industries, Ltd.), 20 parts by mass of a maleimide compound (ma) shown in the structure below (NE-X-9470S, manufactured by DIC Corporation, a compound represented by formula (M1)), 15 parts by mass of maleimide compound (mb) (MIR-3000-70MT, manufactured by Nippon Kayaku Co., Ltd., a compound represented by formula (M3)), 40 parts by mass of the polyphenylene ether compound (B1) having a terminal carbon-carbon unsaturated double bond obtained in Synthesis Example 1, 10 parts by mass of a phosphorus-based flame retardant (PX-200, manufactured by Daihachi Chemical Industry Co., Ltd.), 0.5 parts by mass of a radical polymerization initiator (C1) (Perbutyl P, manufactured by NOF Corporation), and 150 parts by mass of an inorganic filler (SC4500SQ, spherical silica) were mixed and diluted with methyl ethyl ketone to a solids content of 65% by mass, to obtain a varnish. The blending amounts of each component mentioned above are values ​​based on the solid content. The Kraton MD3501 elastomer contains a polymer block containing p-methylstyrene units and hydrogenated or partially hydrogenated butadiene units, and / or hydrogenated or partially hydrogenated isoprene units. The Tg (glass transition temperature) of MD3501 was -10°C (the maximum temperature of the Tan δ peak measured by the DMA method).

[0226] Maleimide compound (ma)

[0227] <Production of Metal Foil-Clad Laminate> The varnish obtained above was applied to an NE glass woven fabric (N3313 S101S, manufactured by Nitto Boseki Co., Ltd.) by impregnation, and the fabric was dried by heating at 155°C for 5 minutes to obtain a prepreg (thickness 0.1 mm) containing 70% by volume of resin composition. The properties of the NE glass woven fabric used are as follows: IPC applicable grade: 3313, density (counts / 25 mm) lengthwise: 60, density (counts / 25 mm) widthwise: 62, thickness (mm): 0.075, mass (g / m ２ ) : 83 One or eight of the obtained prepregs were stacked, and 12 μm thick electrolytic copper foil (3EC-M3-VLP, manufactured by Mitsui Mining & Smelting Co., Ltd.) was placed on both sides, and a pressure of 30 kgf / cm was applied. ２ The laminate was then vacuum pressed at 220° C. for 120 minutes to obtain copper foil-clad laminates with insulating layer thicknesses of 0.1 mm and 0.8 mm.

[0228] <Measurement and Evaluation Methods> <Dielectric Properties> The copper foil-clad laminate (insulating layer thickness 0.8 mm) obtained as described above was etched to remove the copper foil on both sides, then cut to 1.0 mm × 100 mm × 0.8 mm (downsizing). The evaluation sample was dried at 120°C for 60 minutes, and the relative permittivity (Dk) and dielectric loss tangent (Df) at a frequency of 10 GHz were measured by the cavity resonator perturbation method in accordance with JIS C218:2007. The cavity resonator used was manufactured by EM Lab, and the network analyzer used was a P5005A manufactured by Keysight Technologies. The measurement temperature was 23°C. The evaluation was performed as follows. <<Specific permittivity (Dk)>> A: 3.0 or less B: More than 3.0 and less than 3.4 C: More than 3.4 <<Dielectric loss tangent (Df)>> A: 0.0021 or less B: More than 0.0021 and less than 0.0024 C: More than 0.0024

[0229] <CTE (X)> The coefficient of thermal expansion (CTE) was determined by the TMA method (Thermo-Mechanical Analysis) defined in JIS C 6481 5.19 as follows. Specifically, the copper foil on both sides of the copper foil-clad laminate (insulating layer thickness 0.1 mm) obtained above was removed by etching, and the evaluation sample was cut (downsized) to 4.5 mm × 10 mm × 0.1 mm. Using a thermomechanical analyzer (TA Instruments, TMA Q-400), the temperature was raised from 30 ° C. to 320 ° C. at a rate of 10 ° C. per minute, and the coefficient of linear thermal expansion (CTE (X)) in the plane direction from 60 ° C. to 120 ° C. (unit: ppm / ° C.) was measured. The measurement direction was the machine direction (Warp) of the glass cloth of the laminate. ppm is a volume ratio. Other details conform to the above-mentioned JIS C 6481 5.19. Evaluation was made as follows: S: 4 ppm / °C or less A: More than 4 ppm / °C and 5 ppm / °C or less B: More than 5 ppm / °C and 7 ppm / °C or less C: More than 7 ppm / °C and 9 ppm / °C or less D: More than 9 ppm / °C

[0230] <Solder heat resistance> For the copper foil-clad laminate (insulating layer thickness 0.8 mm) obtained above, an evaluation sample (50 mm x 50 mm x 0.8 mm) with copper foil was prepared in accordance with JIS C5012:1992. The evaluation sample was floated in a bath containing solder heated to 288°C for 30 minutes, and the presence or absence of delamination of the evaluation sample was visually confirmed. A and C in the table were evaluated according to the following criteria. A: No delamination within 30 minutes. C: Delamination occurred within 30 minutes.

[0231] <Presence or absence of voids> For the copper foil-clad laminate (insulating layer thickness 0.8 mm) obtained above, an evaluation sample (100 mm x 100 mm x 0.8 mm) with copper foil was prepared, and the copper foil on both sides was removed using an etching solution. The sample after the copper foil removal was visually inspected for the presence or absence of voids. A and C in the table were evaluated according to the following criteria. A: No voids were visually confirmed. C: Voids were visually confirmed.

[0232] Example 2 The same procedure was carried out as in Example 1, except that no inorganic filler (SC4500SQ, spherical silica) was added, and 106.5 parts by mass of an inorganic filler (hollow silica, porosity 32%, average particle size (D50) 4.0 μm) was added.

[0233] Example 3 The same procedures were performed as in Example 1, except that the content of the polyphenylene ether compound (B1) having a terminal carbon-carbon unsaturated double bond obtained in Synthesis Example 1 was changed to 20 parts by mass, and 20 parts by mass of the polymer (va) having a structural unit represented by formula (V) obtained in Synthesis Example 2 was blended.

[0234] Example 4 The same procedure as in Example 1 was carried out, except that the content of the inorganic filler (SC4500SQ, spherical silica) was changed to 250 parts by mass.

[0235] Example 5 The same procedures as in Example 1 were carried out except that the content of the maleimide compound (ma) was 34 parts by mass, the content of the maleimide compound (mb) was 26 parts by mass, the content of the polyphenylene ether compound (B1) having a carbon-carbon unsaturated double bond was 15 parts by mass, and the content of the inorganic filler (SC4500SQ, spherical silica) was 250 parts by mass.

[0236] Comparative Example 1 The same procedures as in Example 1 were carried out except that the elastomer (A1) was not blended, the content of the maleimide compound (ma) was 25 parts by mass, the content of the maleimide compound (mb) was 20 parts by mass, and the content of the polyphenylene ether compound (B1) having a terminal carbon-carbon unsaturated double bond was 45 parts by mass.

[0237] Comparative Example 2 The procedure of Example 1 was repeated except that the elastomer (A1) was replaced with the same amount of elastomer (A2) (SEPTON 2104, manufactured by Kuraray Co., Ltd., SEPS, containing no p-methylstyrene units).

[0238] Comparative Example 3 The same procedure as in Example 1 was carried out except that the content of the inorganic filler (SC4500SQ, spherical silica) was changed to 350 parts by mass.

[0239] Comparative Example 4 The same procedure was carried out as in Example 1, except that 150 parts by mass of inorganic filler (SC4500SQ, spherical silica) was not blended and 319.5 parts by mass of inorganic filler (hollow silica, porosity 32%, average particle size (D50) 4.0 μm) was used.

[0240] Comparative Example 5 The same procedure as in Example 1 was carried out except that the radical polymerization initiator (C1) was not added.

[0241] Comparative Example 6 The same procedure as in Example 1 was carried out except that the inorganic filler (SC4500SQ, spherical silica) was not blended.

[0242] Comparative Example 7 The same procedure as in Example 1 was carried out except that the content of the maleimide compound (ma) was changed to 45 parts by mass, the content of the maleimide compound (mb) was changed to 30 parts by mass, and the polyphenylene ether compound (B1) having a terminal carbon-carbon unsaturated double bond obtained in Synthesis Example 1 was not blended.

[0243] Comparative Example 8 The same procedures as in Example 1 were carried out except that the content of the maleimide compound (ma) was changed to 39 parts by mass, the content of the maleimide compound (mb) was changed to 26 parts by mass, and the content of the polyphenylene ether compound (B1) having a terminal carbon-carbon unsaturated double bond obtained in Synthesis Example 1 was changed to 10 parts by mass.

[0244]

Claims

1. A resin composition comprising an elastomer (A), a thermosetting compound (B), a radical polymerization initiator (C), and a filler (D), wherein the elastomer (A) comprises a polymer block (a1) containing a styrene compound unit having a radical reactive group and a conjugated diene compound unit, the thermosetting compound (B) comprises a resin (E) having two or more vinylbenzyl groups at its terminals, the content of the filler (D) is 1 to 300 parts by mass per 100 parts by mass of resin solids, and the mass ratio ((A) / (E)) of the elastomer (A) to the resin (E) having two or more vinylbenzyl groups at its terminals is 0.01 to 1.

1.

2. The resin composition according to claim 1, wherein the radical reactive group comprises a methyl group.

3. The resin composition according to claim 1, wherein the styrene compound unit having a radical reactive group includes a p-methylstyrene unit.

4. The resin composition according to claim 1 or 2, wherein the conjugated diene compound units include butadiene units and / or isoprene units.

5. The resin composition according to claim 1 or 2, wherein the conjugated diene compound units include hydrogenated or partially hydrogenated butadiene units and / or hydrogenated or partially hydrogenated isoprene units.

6. The resin composition according to claim 1 or 2, wherein the conjugated diene compound units contain butylene units and / or ethylene units.

7. A resin composition according to claim 1, wherein the elastomer (A) further comprises a polymer block (a2) containing a styrene compound unit which may have a radical reactive group, and / or a polymer block (a3) ​​containing a conjugated diene compound unit.

8. The resin composition according to claim 7, wherein the styrene compound units optionally having a radical reactive group in the polymer block (a2) contain p-methylstyrene units, and the conjugated diene compound units in the polymer block (a3) ​​contain hydrogenated or partially hydrogenated butadiene units and / or hydrogenated or partially hydrogenated isoprene units.

9. The resin composition according to claim 1 or 2, wherein the content of the styrene compound unit having a radical reactive group in 100% by mass of the polymer block (a1) is 10 to 80% by mass.

10. A resin composition according to claim 1 or 2, wherein the content of styrene compound units having a radical reactive group is 10 to 70 mass % in 100 mass % of the elastomer (A).

11. The resin composition according to claim 1 or 2, wherein the elastomer (A) has a maximum temperature of Tan δ peak in a range of −30 to 80° C. as determined by dynamic mechanical analysis (DMA) at a frequency of 10 rad / s.

12. The resin composition according to claim 1 or 2, wherein the content of the elastomer (A) is 0.5 to 30 parts by mass per 100 parts by mass of the resin solid content.

13. The styrene compound units having a radical reactive group comprise p-methylstyrene units, the conjugated diene compound units comprise hydrogenated or partially hydrogenated butadiene units and / or hydrogenated or partially hydrogenated isoprene units, the elastomer (A) further comprises a polymer block (a2) comprising a styrene compound unit optionally having a radical reactive group and / or a polymer block (a3) ​​comprising a conjugated diene compound unit, the styrene compound units optionally having a radical reactive group of the polymer block (a2) comprise p-methylstyrene units, and the conjugated diene compound units of the polymer block (a3) ​​comprise hydrogenated or partially hydrogenated butadiene units and / or hydrogenated or partially hydrogenated isoprene units, the content of the styrene compound units having a radical reactive group in 100% by mass of the polymer block (a1) is 10 to 80% by mass, and the content of the styrene compound units having a radical reactive group in 100% by mass of the elastomer (A) is 10 to 70% by mass, 2. The resin composition according to claim 1, wherein the elastomer (A) has a maximum temperature of Tan δ peak in a dynamic mechanical analysis (DMA) measured at a frequency of 10 rad / s of −30 to 80° C., and the content of the elastomer (A) is 0.5 to 30 parts by mass per 100 parts by mass of resin solid content.

14. The resin composition according to claim 1 to 3, 7, 8 or 13, wherein the resin (E) having two or more vinylbenzyl groups at its terminals comprises a polyphenylene ether compound having two or more vinylbenzyl groups at its terminals and / or a polymer having a structural unit represented by formula (V). (In formula (V), Ar represents an aromatic hydrocarbon linking group. * represents a bonding position.) 15. The resin composition according to claim 1 to 3, 7, 8 or 13, wherein the resin (E) having two or more vinylbenzyl groups at its terminals comprises a polyphenylene ether compound represented by formula (OP). (In formula (OP), X represents an aromatic group, and —(Y—O) ｎ１ - represents a polyphenylene ether structure, n1 represents an integer of 1 to 100, and n2 represents an integer of 1 to 4. Rx is a group represented by formula (Rx-1). (In formula (Rx-1), R １ , R ２ , and R ３ each independently represents a hydrogen atom, an alkyl group, an alkenyl group, or an alkynyl group. * represents a bonding site with an oxygen atom. Each Mc independently represents a hydrocarbon group having 1 to 12 carbon atoms. z represents an integer of 0 to 4. r represents an integer of 0 to 6.

16. A resin composition according to claim 1 to 3, 7, 8 or 13, wherein the content of the resin (E) having two or more vinylbenzyl groups at its terminals is 1 part by mass or more and 60 parts by mass or less per 100 parts by mass of the resin solids in the resin composition.

17. The resin composition according to claim 13, wherein the thermosetting compound (B) further comprises a maleimide compound.

18. The resin composition according to claim 1, 2, 3, 7, 8 or 13, wherein the radical polymerization initiator (C) comprises an organic peroxide.

19. The resin composition according to claim 1, 2, 3, 7, 8 or 13, wherein the filler (D) comprises hollow silica.

20. The resin composition according to claim 1, 2, 3, 7, 8 or 13, further comprising a flame retardant.

21. The resin composition according to claim 1, wherein the thermosetting compound (B) contains an aromatic-containing resin having a terminal carbon-carbon double bond, the thermosetting compound (B) further contains a maleimide compound, the radical polymerization initiator (C) contains an organic peroxide, the filler (D) contains hollow silica, and the resin composition further contains a flame retardant.

22. A cured product of the resin composition according to claim 1, 2, 3, 7, 8 or 13.

23. A prepreg formed from a substrate and the resin composition according to claim 1, 2, 3, 7, 8 or 13.

24. A metal foil clad laminate comprising at least one layer formed from the prepreg of claim 23 and metal foil disposed on one or both sides of the layer formed from the prepreg.

25. A resin composite sheet comprising a support and a layer formed from the resin composition according to claim 1, 2, 3, 7, 8 or 13, disposed on the surface of the support.

26. A printed wiring board comprising an insulating layer and a conductor layer disposed on the surface of the insulating layer, wherein the insulating layer comprises a layer formed from the resin composition described in claim 1, 2, 3, 7, 8 or 13.

27. A semiconductor device including the printed wiring board according to claim 26.